Parametric resonance of optically trapped aerosols (2007)
Leonardo, R.Di., Ruocco, G., Leach, J., Padgett, M.J., Wright, A.*, Girkin, J.M.*, ...
The Brownian dynamics of an optically trapped water droplet are investigated across the transition from over- to underdamped oscillations. The spectrum of position fluctuations evolves from a...
Parametric resonance of optically trapped aerosols (2007)
Leonardo, R.Di., Ruocco, G., Leach, J., Padgett, M.J., Wright, A., Girkin, J.M., ...
The Brownian dynamics of an optically trapped water droplet are investigated across the transition from over- to underdamped oscillations. The spectrum of position fluctuations evolves from a...
Parametric resonance of optically trapped aerosols (2007)
Leonardo, R.Di., Ruocco, G., Leach, J., Padgett, M.J., Wright, A., Girkin, J.M., ...
The Brownian dynamics of an optically trapped water droplet are investigated across the transition from over- to underdamped oscillations. The spectrum of position fluctuations evolves from a...
Parametric resonance of optically trapped aerosols (2007)
Di Leonardo, R., Ruocco, G., Leach, J., Padgett, M.J., Wright, A.J., Girkin, J.M., ...
The Brownian dynamics of an optically trapped water droplet are investigated across the transition from over- to underdamped oscillations. The spectrum of position fluctuations evolves from a...
Optical ferris wheel for ultracold atoms (2007)
Franke-Arnold, S., Leach, J., Padgett, M.J., Lembessis, D., Ellinas, D., Wright, A.J., ...
We propose a versatile optical ring lattice suitable for trapping cold and quantum degenerate atomic samples. We demonstrate the realisation of intensity patterns from pairs of Laguerre-Gauss...
Optical ferris wheel for ultracold atoms (2007)
Franke-Arnold, S., Leach, J., Padgett, M.J., Lembessis, D., Ellinas, D., Wright, A.J., ...
We propose a versatile optical ring lattice suitable for trapping cold and quantum degenerate atomic samples. We demonstrate the realisation of intensity patterns from pairs of Laguerre-Gauss...
Optical ferris wheel for ultracold atoms (2007)
Franke-Arnold, S., Leach, J., Padgett, M.J., Lembessis, D., Ellinas, D., Wright, A.J., ...
We propose a versatile optical ring lattice suitable for trapping cold and quantum degenerate atomic samples. We demonstrate the realisation of intensity patterns from pairs of Laguerre-Gauss...
Parametric Resonance of Optically Trapped Aerosols (2007)
Di Leonardo, R., Ruocco, G., Leach, J., Padgett, M. J., Wright, A. J., Girkin, J. M., ...
The Brownian dynamics of an optically trapped water droplet are investigated across the transition from over to under-damped oscillations. The spectrum of position fluctuations evolves from a...
Optical ferris wheel for ultracold atoms (2006)
Franke-Arnold, S., Leach, J., Padgett, M. J., Lembessis, V. E., Ellinas, D., Wright, A. J., ...
We propose a versatile optical ring lattice suitable for trapping cold and quantum degenerate atomic samples at discrete angular positions. We demonstrate the realisation of intensity patterns...
Confocal and multiphoton microscopy for imaging at depth in living tissue (2006)
Girkin, J.M.*, Wright, A.J.*, Poland, S.*, Patterson, B.A., Padgett, M.J
The desire to image with sub micron resolution at ever increasing depths into living samples is providing optical physicists with the latest in a long line of challenges presented by life science...
Confocal and multiphoton microscopy for imaging at depth in living tissue (2006)
Girkin, J.M., Wright, A.J., Poland, S., Patterson, B.A., Padgett, M.J.
The desire to image with sub micron resolution at ever increasing depths into living samples is providing optical physicists with the latest in a long line of challenges presented by life science...
Confocal and multiphoton microscopy for imaging at depth in living tissue (2006)
Girkin, J.M., Wright, A.J., Poland, S., Patterson, B.A., Padgett, M.J.
The desire to image with sub micron resolution at ever increasing depths into living samples is providing optical physicists with the latest in a long line of challenges presented by life science...
Illustrations of optical vortices in three dimensions (2006)
K. O'Holleran; University Of Glasgow, M. R. Dennis; University Of Southampton, M. J. Padgett; Unversity Of Glasgow
Optical vortices (phase singularities) arise from interference and are threads of darkness embedded within light fields. Although usually visualised in terms of their points of intersection with an...
Monk, Stephen, Skeldon, K. D., McMillan, L. C., Wyse, C. A., Gibson, G., Patterson, C., ...
There is increasing interest in ethane (C2H6) in exhaled breath as a non-invasive marker of oxidative stress (OS) and thereby a potential indicator of disease. However, the lack of real-time...
Wright, A.J., Poland, S.P., Patterson, B.A., Girkin, J.M.*, Gibson, G.M., Padgett, M.J.
A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track...
Wright, A.J., Poland, S.P., Patterson, B.A., Girkin, J.M., Gibson, G.M., Padgett, M.J.
A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track...
Wright, A.J., Poland, S.P., Patterson, B.A., Girkin, J.M., Gibson, G.M., Padgett, M.J.
A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track...
Illustrations of optical vortices in three dimensions (2006)
O'Holleran, K., Dennis, M.R., Padgett, M.J.
Optical vortices (phase singularities) arise from interference and are threads of darkness embedded within light fields. Although usually visualised in terms of their points of intersection with an...
Wright, A.J., Patterson, B.A., Poland, S.P., Girkin, J.M.*, Gibson, G.M., Padgett, M.J.
A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track...
Wright, A.J., Patterson, B.A., Poland, S.P., Girkin, J.M., Gibson, G.M., Padgett, M.J.
A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track...
Wright, A.J., Patterson, B.A., Poland, S.P., Girkin, J.M., Gibson, G.M., Padgett, M.J.
A dynamic closed-loop method for focus tracking using a spatial light modulator and a deformable membrane mirror within a confocal microscope is described. We report that it is possible to track...
Generation of achromatic bessel beams using a compensated spatial light modulator (2006)
Leach, J., Gibson, G.M., Padgett, M.J., Esposito, E., Wright, A., Girkin, J.M., ...
We report the creation of white-light, achromatic Bessel beams using a spatial light modulator and a prism to compensate for the dispersion. Unlike the Bessel beam created by a refractive axicon,...
Jordan, P., Cooper, J., McNay, G., Docherty, F.T., Graham, D., Smith, W.E., ...
Silica particles were partially coated with silver, and a suitable chromophore, such that they could be trapped within an optical tweezers system and simultaneously be excited to emit a...
Jordan, P., Cooper, J., McNay, G., Docherty, F.T., Graham, D., Smith, W.E., ...
Silica particles were partially coated with silver, and a suitable chromophore, such that they could be trapped within an optical tweezers system and simultaneously be excited to emit a...
Jordan, P., Cooper, J., McNay, G., Docherty, F.T., Graham, D., Smith, W.E., ...
Silica particles were partially coated with silver, and a suitable chromophore, such that they could be trapped within an optical tweezers system and simultaneously be excited to emit a...
Leach, J., Dennis, M.R., Courtial, J., Padgett, M.J.
Optical vortices generically arise when optical beams are combined. Recently, we reported how several laser beams containing optical vortices could be combined to form optical vortex loops, links and...
Aiuppa, A., Inguaggiato, S., McGonigle, A. J. S., O'Dwyer, M., Oppenheimer, C., Padgett, M.J., ...
We present here new measurements of sulfur dioxide and hydrogen sulfide emissions from Vulcano, Etna, and Stromboli (Italy), made by direct sampling at vents and by filter pack and ultraviolet...
Aiuppa, A.; Dipartimento Chimica E Fisica Della Terra Ed Applicazioni, Università Di Palermo, Palermo, Italy, Inguaggiato, S.; Istituto Nazionale Di Geofisica E Vulcanologia, Sezione Palermo, Palermo, Italia, McGonigle, A. J. S.; Department Of Geography, University Of Cambridge, Cambridge, UK, O'Dwyer, M.; Department Of Physics And Astronomy, University Of Glasgow, Glasgow, UK, Oppenheimer, C.; Department Of Geography, University Of Cambridge, Cambridge, UK, Padgett, M. J.; Department Of Physics And Astronomy, University Of Glasgow, Glasgow, UK, ...
We present here new measurements of sulfur dioxide and hydrogen sulfide emissions from Vulcano, Etna, and Stromboli (Italy), made by direct sampling at vents and by filter pack and ultraviolet...
Creating permanent 3D arrangements of isolated cells using holographic optical tweezers (2005)
Jordan, P., Leach, J., Padgett, M.J., Blackburn, P., Isaacs, N., Goksor, M., ...
Reports the creation of permanent 3D configurations of cells, at predefined positions, within a gelatin matrix. The technique used holographic optical tweezers to manipulate individual E. coli within...
Red microchip VECSEL array (2005)
Hastie, J.E., Morton, L.G., Calvez, S., Dawson, M.D., Leinonen, T., Pessa, M., ...
We report an InGaP/AlInGaP/GaAs microchip vertical-external-cavity surface emitting laser operating directly at red wavelengths and demonstrate its potential for array-format operation. Optical...
Creating permanent 3D arrangements of isolated cells using holographic optical tweezers (2005)
Jordan, P., Leach, J., Padgett, M.J., Blackburn, P., Isaacs, N., Goksor, M., ...
Reports the creation of permanent 3D configurations of cells, at predefined positions, within a gelatin matrix. The technique used holographic optical tweezers to manipulate individual E. coli within...
Red microchip VECSEL array (2005)
Hastie, J.E., Morton, L.G., Calvez, S., Dawson, M.D., Leinonen, T., Pessa, M., ...
We report an InGaP/AlInGaP/GaAs microchip vertical-external-cavity surface emitting laser operating directly at red wavelengths and demonstrate its potential for array-format operation. Optical...
Creating permanent 3D arrangements of isolated cells using holographic optical tweezers (2005)
Jordan, P., Leach, J., Padgett, M.J., Blackburn, P., Isaacs, N., Goksor, M., ...
Reports the creation of permanent 3D configurations of cells, at predefined positions, within a gelatin matrix. The technique used holographic optical tweezers to manipulate individual E. coli within...
Red microchip VECSEL array (2005)
Hastie, J.E., Morton, L.G., Calvez, S., Dawson, M.D., Leinonen, T., Pessa, M., ...
We report an InGaP/AlInGaP/GaAs microchip vertical-external-cavity surface emitting laser operating directly at red wavelengths and demonstrate its potential for array-format operation. Optical...
Leach, J., Dennis, M. R., Courtial, J., Padgett, M. J.
Optical vortices generically arise when optical beams are combined. Recently, we reported how several laser beams containing optical vortices could be combined to form optical vortex loops, links and...
Leach, J., Courtial, J., Skeldon, K., Barnett, S.M.*, Franke-Arnold, S., Padgett, M.J.
We propose interferometric methods capable of measuring either the total angular momentum, or simultaneously measuring the spin and orbital angular momentum of single photons. This development...
Leach, J., Courtial, J., Skeldon, K., Barnett, S.M., Franke-Arnold, S., Padgett, M.J.
We propose interferometric methods capable of measuring either the total angular momentum, or simultaneously measuring the spin and orbital angular momentum of single photons. This development...
Leach, J., Courtial, J., Skeldon, K., Barnett, S.M., Franke-Arnold, S., Padgett, M.J.
We propose interferometric methods capable of measuring either the total angular momentum, or simultaneously measuring the spin and orbital angular momentum of single photons. This development...
Defining the trapping limits of holographical optical tweezers (2004)
Sinclair, G., Jordan, P., Leach, J., Padgett, M.J., Cooper, J.
We report on the limitations of using a spatial light modulator (SLM) within optical tweezers to produce both lateral and axial displacements. We find that lateral displacements of optical traps are...
Free-space information transfer using light beams carrying orbital angular momentum (2004)
Gibson, G., Courtial, J., Padgett, M.J., Vasnetsov, M., Pas'ko, V., Barnett, S.M., ...
We demonstrate the transfer of information encoded as orbital angular momentum (OAM) states of a light beam. The transmitter and receiver units are based on spatial light modulators, which prepare or...
Three-dimensional optical trapping of partially silvered silica microparticles (2004)
Jordan, P., Cooper, J., Mcnay, G., Docherty, F.T., Smith, W.E., Sinclair, G., ...
We demonstrate three-dimensional trapping of micrometer- diameter silica particles, partially coated with silver, within conventional optical tweezers. Although metallic particles are usually...
Laser beams: knotted threads of darkness (2004)
Leach, J., Dennis, M.R., Courtial, J., Padgett, M.J.
Dark lines within a laser beam can be manipulated to form stable vortex knots. Destructive interference may lead to complete cancellation when light waves travelling in different directions cross,...
Observation of the vortex structure of a non-integer vortex beam (2004)
Leach, J., Yao, E., Padgett, M.J.
An optical beam with an e(i/phi) phase structure carries an orbital angular momentum of lh per photon. For integer l values, the phase fronts of such beams form perfect helices with a single...
The mechanism for energy transfer in the rotational frequency shift of a light beam (2004)
It is well known that when a light beam containing angular momentum is rotated about the propagation axis it is shifted in frequency. The magnitude of the shift is equal to the angular momentum per...
Sinclair, G., Leach, J., Jordan, P., Gibson, G., Yao, E., Laczik, Z.J., ...
Phase-hologram patterns that can shape the intensity distribution of a light beam in several planes simultaneously can be calculated with an iterative Gerchberg-Saxton algorithm [T. Haist et al.,...
3D manipulation of particles into crystal structures using holographic optical tweezers (2004)
Leach, J., Sinclair, G., Jordan, P., Courtial, J., Padgett, M.J., Cooper, J., ...
We have developed holographic optical tweezers that can manipulate many particles simultaneously in three dimensions in order to create micro-crystal structures that extend over many tens of microns....
Garces-Chavez, V., McGloin, D., Padgett, M.J., Dultz, W., Schmitzer, H., Dholakia, K.
We observe the spinning and orbital motion of a microscopic particle trapped within a multiringed light beam that arises from the transfer of the spin and orbital components of the light's angular...
Performance of a rotating aperture for spinning and orienting objects in optical tweezers (2003)
Forrester, A., Courtial, J., Padgett, M.J.
The spinning of asymmetric objects trapped within optical tweezers that have a rotating rectangular aperture inserted into the trapping laser beam is characterized. The measured maximum rotation...
Simplified measurement of the orbital angular momentum of single photons (2003)
Haiqing, Wei, Xin, Xue, Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., ...
We describe a simplification of a recent approach for sorting photons according to their orbital angular momentum (OAM) [Leach et al., Phys. Rev. Lett. 88 (2002) 257901]. The original cascade of...
Classic-fractal eigenmodes of unstable canonical resonators (2003)
Watterson, C.M.G., Padgett, M.J., Courtial, J.
It was recently shown that intensity cross-sections through the eigenmodes of canonical unstable resonators with polygonal apertures can have the statistical scaling behaviour of fractals. Here we...
Fractals in pixellated video feedback (2003)
Leach, J., Padgett, M.J., Courtial, J.
Using experiments and computer simulations, we show that video feedback with a pixel-based monitor can lead to self-similar stationary patterns. We found an astonishing variety of such patterns,...
Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy (2003)
O'Dwyer, M., Padgett, M.J., McGonigle, A. J. S., Oppenheimer, C., Inguaggiato, S.
Sulphur speciation in volcanic gases acts as a major redox buffer, and H2S/SO2 ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids....
Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy (2003)
O'Dwyer, M.; Department Of Physics And Astronomy, University Of Glasgow, Glasgow, UK, Padgett, M. J.; Department Of Physics And Astronomy, University Of Glasgow, Glasgow, UK, McGonigle, A. J. S.; Department Of Geography, University Of Cambridge, Cambridge, UK, Oppenheimer, C.; Department Of Geography, University Of Cambridge, Cambridge, UK, Inguaggiato, S.; Istituto Nazionale Di Geofisica E Vulcanologia, Sezione Palermo, Palermo, Italia
Sulphur speciation in volcanic gases acts as a major redox buffer, and H2S/SO2 ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids....
Optically controlled three-dimensional rotation of microscopic objects (2003)
Bingelyte, V., Leach, J., Courtial, J., Padgett, M.J.
An approach of optically controlled three-dimensional rotation of microscopic objects was studied. A spatially light modulator was used to create a pair of closely separated optical traps holding...
Preface: Optical tweezers in a new light (2003)
Molloy, J.E., Dholakia, K., Padgett, M.J.
Optical tweezers were invented in the mid-1980s by Arthur Ashkin and co-workers at the Bell Telephone Laboratories. Since then there has been a steady stream of developments and applications,...
Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy (2003)
O'Dwyer, M., Padgett, M.J., McGonigle, A.J.S., Oppenheimer, C., Inguaggiato, S.
Sulphur speciation in volcanic gases acts as a major redox buffer, and H2S/SO2 ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids....
A multimode fibre-coupled compact optical wavelength meter based on Wollaston prisms (2003)
We present a compact, portable, and mechanically robust instrument for measuring optical wavelength based on an arrangement of four Wollaston prisms that forms spatially localised fringes in a plane...
Why are the eigenmodes of stable laser resonators structurally stable? (2002)
Forrester, A., Lonnqvist, M., Padgett, M.J., Courtial, J.
Optical resonators are usually examined wave optically. We consider geometrical imaging in stable canonical resonators. We show that, with important exceptions related to eigenmode degeneracy, stable...
Lights, action: optical tweezers (2002)
Optical tweezers were first realized 15 years ago by Arthur Ashkin and co-workers at the Bell Telephone Laboratories. Since that time there has been a steady stream of developments and applications,...
Measuring the orbital angular momentum of a single photon (2002)
Leach, J., Padgett, M.J., Barnett, S.M.*, Franke-Arnold, S., Courtial, J.
We propose an interferometric method for measuring the orbital angular momentum of single photons. We demonstrate its viability by sorting four different orbital angular momentum states, and are thus...
Measuring the orbital angular momentum of a single photon (2002)
Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., Courtial, J.
We propose an interferometric method for measuring the orbital angular momentum of single photons. We demonstrate its viability by sorting four different orbital angular momentum states, and are thus...
Measuring the orbital angular momentum of a single photon (2002)
Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., Courtial, J.
We propose an interferometric method for measuring the orbital angular momentum of single photons. We demonstrate its viability by sorting four different orbital angular momentum states, and are thus...
Measuring the orbital angular momentum of a single photon (2002)
Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., Courtial, J.
We propose an interferometric method for measuring the orbital angular momentum of single photons. We demonstrate its viability by sorting four different orbital angular momentum states, and are thus...
Rotational control within optical tweezers by use of a rotating aperture (2002)
We demonstrate a simplified method of rotational control of objects trapped within optical tweezers that does not require high-order modes, interferometric precision, or computer-controlled optical...
Two-photon entanglement of orbital angular momentum states (2002)
Franke-Arnold, S., Barnett, S.M., Padgett, M.J., Allen, L.
We investigate the orbital angular momentum correlation of a photon pair created in a spontaneous parametric down-conversion process. We show how the conservation of the orbital angular momentum in...
Intrinsic and extrinsic nature of the orbital angular momentum of a light beam (2002)
O'Neil, A.T., MacVicar, I., Allen, L., Padgett, M.J.
We explain that, unlike the spin angular momentum of a light beam which is always intrinsic, the orbital angular momentum may be either extrinsic or intrinsic. Numerical calculations of both spin and...
Response to Question #79. Does a plane wave carry spin angular momentum? (2002)
No abstract available.
Holographic generation and orbital angular momentum of high-order mathieu beams (2002)
Chavez-Cerda, S., Padgett, M.J., Allison, I., New, G.H.C., Gutierrez-Vega, J.C., O'Neil, A.T., ...
We report the first experimental generation of high-order Mathieu beams and confirm their propagation invariance over a limited range. In our experiment we use a computer-generated phase hologram....
A compact fluorescence spectroscopic tool for cancer detection (2002)
Nadeau, V., Hamdan, K., Hewett, J., Makaryceva, J., Tait, I., Cuschieri, A., ...
We describe a compact fluorescence spectroscopic tool for in vivo point monitoring of aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence and autofluorescence, as a non-invasive...
Wollaston prism-based digital laser wavelength meter (2002)
We present a device designed to measure laser output wavelength and based on Wollaston prisms and barium borate (BBO) crystal polarizers. The arrangement generates a localized fringe plane...
Orbital angular momentum exchange in cylindrical-lens mode converters (2002)
Cylindrical-lens mode converters (Beijersbergen M. W., Allen L., van der Veen H. E. L. O. and Woerdman J. P. 1993 Opt. Commun. 96 123-32) are used to transform between Hermite-Gaussian and...
Construction of a database of benzene biological monitoring (2002)
Pople, J.E., Ball, R.L., Padgett, M.J., Aston, J.P.
Biological monitoring of occupational exposure to benzene has been conducted in the petroleum, steel and chemical industries. The urinary benzene-specific biomarker, S-phenylmercapturic acid (PMA),...
Mueller matrix error correction for a fringe-free interferometry system (2001)
Begbie, M.L., Sibbett, W., Padgett, M.J.
We present an automated surface profiling system based on a shearing interferometer, in which precise measurement of the polarization states eliminates fringe ambiguity. A full error correction based...
Image processing: Fractals in pixellated video feedback (2001)
Courtial, J., Leach, J., Padgett, M.J.
Video feedback occurs whenever a video camera is directed at a screen displaying the image currently being recorded by the camera. It can be observed in everyday situations, for example at sporting...
Fractal generation using optical feedback with incoherent gain (2001)
Forrester, A., Courtial, J., Padgett, M.J.
We present an optical system for the spontaneous generation of self-similar fractal patterns. The system configuration is that of a ring cavity containing a lens array to form multiple, but laterally...
Axial and lateral trapping efficiency of Laguerre-Gaussian modes in inverted optical tweezers (2001)
Within inverted optical tweezers we measure both the lateral and axial trapping efficiency obtained with Gaussian and high-order Laguerre-Gaussian beams. Our results confirm that, for larger...
Transfer of orbital angular momentum to metal particles confined using optical tweezers (2001)
Using Laguerre-Gaussian beams in an inverted optical tweezers geometry we observe that silver particles, 2 mu m in diameter, are confined to an annulus around the outside of the beam. This annulus is...
A novel mechanism is proposed for the generation of self-similar structure over a limited range of length scales. Our mechanism, which we call the monitor-outside-a-monitor effect, comprises repeated...
We report a new mechanism for trapping metallic particles in inverted optical tweezers. The particles are loosely confined, in three dimensions, to an annular region just below the beam waist where...
A computer-generated hologram is used to form an optical beam with a localized intensity null at its focus. The beam is a superposition of two Laguerre-Gaussian modes that are phased so that they...
Aberrations introduced by a lens made from a birefringent material (2000)
Lesso, J.P., Duncan, A.J., Sibbett, W., Padgett, M.J.
We incorporate an algorithm for ray tracing in birefringent media into a full ray-tracing package based on the Mathematica software application. To validate the package, we compare the calculated and...
Within a ray-optical approximation we show that there is a limit to the orbital angular momentum per unit energy that can be focused onto a small particle. This limit depends solely on the geometry...
The rate of electromagnetic energy flow per unit area, the Poynting vector, is defined and discussed in all books of electromagnetism. The vector and its associated linear momentum density is,...
Generation of self-reproducing fractal patterns using a multiple imaging system with feedback (2000)
We present a simple optical system for producing self-similar fractal patterns. The key component comprises three adjacent lenses, which form multiple images of a pattern displayed on a monitor. The...
Orbital angular momentum, optical spanners, and rotational frequency shift (2000)
Light possesses both spin and orbital angular momentum. Whereas the spin component arises from the spin of individual photons and is associated with circular polarization, the orbital component...
Matrix formulation for the propagation of light beams with orbital and spin angular momenta (1999)
Allen, L., Courtial, J., Padgett, M.J.
Jones matrices describe the polarization, or spin angular momentum, of a light beam as it passes through an optical system. We devise an equivalent of the Jones matrix formulation for light...
Matrix formulation for the propagation of light beams with orbital and spin angular momenta
Allen, L., Courtial, J., Padgett, M.J.
Jones matrices describe the polarization, or spin angular momentum, of a light beam as it passes through an optical system. We devise an equivalent of the Jones matrix formulation for light...
The rate of electromagnetic energy flow per unit area, the Poynting vector, is defined and discussed in all books of electromagnetism. The vector and its associated linear momentum density is,...
Response to Question #79. Does a plane wave carry spin angular momentum?
No abstract available.
A computer-generated hologram is used to form an optical beam with a localized intensity null at its focus. The beam is a superposition of two Laguerre-Gaussian modes that are phased so that they...
Mueller matrix error correction for a fringe-free interferometry system
Begbie, M.L., Sibbett, W., Padgett, M.J.
We present an automated surface profiling system based on a shearing interferometer, in which precise measurement of the polarization states eliminates fringe ambiguity. A full error correction based...
Optically controlled three-dimensional rotation of microscopic objects
Bingelyte, V., Leach, J., Courtial, J., Padgett, M.J.
An approach of optically controlled three-dimensional rotation of microscopic objects was studied. A spatially light modulator was used to create a pair of closely separated optical traps holding...
Holographic generation and orbital angular momentum of high-order mathieu beams
Chavez-Cerda, S., Padgett, M.J., Allison, I., New, G.H.C., Gutierrez-Vega, J.C., O'Neil, A.T., ...
We report the first experimental generation of high-order Mathieu beams and confirm their propagation invariance over a limited range. In our experiment we use a computer-generated phase hologram....
Generation of self-reproducing fractal patterns using a multiple imaging system with feedback
We present a simple optical system for producing self-similar fractal patterns. The key component comprises three adjacent lenses, which form multiple images of a pattern displayed on a monitor. The...
Within a ray-optical approximation we show that there is a limit to the orbital angular momentum per unit energy that can be focused onto a small particle. This limit depends solely on the geometry...
A novel mechanism is proposed for the generation of self-similar structure over a limited range of length scales. Our mechanism, which we call the monitor-outside-a-monitor effect, comprises repeated...
Fractal generation using optical feedback with incoherent gain
Forrester, A., Courtial, J., Padgett, M.J.
We present an optical system for the spontaneous generation of self-similar fractal patterns. The system configuration is that of a ring cavity containing a lens array to form multiple, but laterally...
Performance of a rotating aperture for spinning and orienting objects in optical tweezers
Forrester, A., Courtial, J., Padgett, M.J.
The spinning of asymmetric objects trapped within optical tweezers that have a rotating rectangular aperture inserted into the trapping laser beam is characterized. The measured maximum rotation...
Why are the eigenmodes of stable laser resonators structurally stable?
Forrester, A., Lonnqvist, M., Padgett, M.J., Courtial, J.
Optical resonators are usually examined wave optically. We consider geometrical imaging in stable canonical resonators. We show that, with important exceptions related to eigenmode degeneracy, stable...
Two-photon entanglement of orbital angular momentum states
Franke-Arnold, S., Barnett, S.M., Padgett, M.J., Allen, L.
We investigate the orbital angular momentum correlation of a photon pair created in a spontaneous parametric down-conversion process. We show how the conservation of the orbital angular momentum in...
Garces-Chavez, V., McGloin, D., Padgett, M.J., Dultz, W., Schmitzer, H., Dholakia, K.
We observe the spinning and orbital motion of a microscopic particle trapped within a multiringed light beam that arises from the transfer of the spin and orbital components of the light's angular...
Simplified measurement of the orbital angular momentum of single photons
Haiqing, Wei, Xin, Xue, Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., ...
We describe a simplification of a recent approach for sorting photons according to their orbital angular momentum (OAM) [Leach et al., Phys. Rev. Lett. 88 (2002) 257901]. The original cascade of...
Fractals in pixellated video feedback
Leach, J., Padgett, M.J., Courtial, J.
Using experiments and computer simulations, we show that video feedback with a pixel-based monitor can lead to self-similar stationary patterns. We found an astonishing variety of such patterns,...
Leach, J., Courtial, J., Skeldon, K., Barnett, S.M., Franke-Arnold, S., Padgett, M.J.
We propose interferometric methods capable of measuring either the total angular momentum, or simultaneously measuring the spin and orbital angular momentum of single photons. This development...
Measuring the orbital angular momentum of a single photon
Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., Courtial, J.
We propose an interferometric method for measuring the orbital angular momentum of single photons. We demonstrate its viability by sorting four different orbital angular momentum states, and are thus...
Aberrations introduced by a lens made from a birefringent material
Lesso, J.P., Duncan, A.J., Sibbett, W., Padgett, M.J.
We incorporate an algorithm for ray tracing in birefringent media into a full ray-tracing package based on the Mathematica software application. To validate the package, we compare the calculated and...
Lights, action: optical tweezers
Optical tweezers were first realized 15 years ago by Arthur Ashkin and co-workers at the Bell Telephone Laboratories. Since that time there has been a steady stream of developments and applications,...
Preface: Optical tweezers in a new light
Molloy, J.E., Dholakia, K., Padgett, M.J.
Optical tweezers were invented in the mid-1980s by Arthur Ashkin and co-workers at the Bell Telephone Laboratories. Since then there has been a steady stream of developments and applications,...
A compact fluorescence spectroscopic tool for cancer detection
Nadeau, V., Hamdan, K., Hewett, J., Makaryceva, J., Tait, I., Cuschieri, A., ...
We describe a compact fluorescence spectroscopic tool for in vivo point monitoring of aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence and autofluorescence, as a non-invasive...
Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy
O'Dwyer, M., Padgett, M.J., McGonigle, A.J.S., Oppenheimer, C., Inguaggiato, S.
Sulphur speciation in volcanic gases acts as a major redox buffer, and H2S/SO2 ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids....
A multimode fibre-coupled compact optical wavelength meter based on Wollaston prisms
We present a compact, portable, and mechanically robust instrument for measuring optical wavelength based on an arrangement of four Wollaston prisms that forms spatially localised fringes in a plane...
Wollaston prism-based digital laser wavelength meter
We present a device designed to measure laser output wavelength and based on Wollaston prisms and barium borate (BBO) crystal polarizers. The arrangement generates a localized fringe plane...
Axial and lateral trapping efficiency of Laguerre-Gaussian modes in inverted optical tweezers
Within inverted optical tweezers we measure both the lateral and axial trapping efficiency obtained with Gaussian and high-order Laguerre-Gaussian beams. Our results confirm that, for larger...
Intrinsic and extrinsic nature of the orbital angular momentum of a light beam
O'Neil, A.T., MacVicar, I., Allen, L., Padgett, M.J.
We explain that, unlike the spin angular momentum of a light beam which is always intrinsic, the orbital angular momentum may be either extrinsic or intrinsic. Numerical calculations of both spin and...
Rotational control within optical tweezers by use of a rotating aperture
We demonstrate a simplified method of rotational control of objects trapped within optical tweezers that does not require high-order modes, interferometric precision, or computer-controlled optical...
We report a new mechanism for trapping metallic particles in inverted optical tweezers. The particles are loosely confined, in three dimensions, to an annular region just below the beam waist where...
Transfer of orbital angular momentum to metal particles confined using optical tweezers
Using Laguerre-Gaussian beams in an inverted optical tweezers geometry we observe that silver particles, 2 mu m in diameter, are confined to an annulus around the outside of the beam. This annulus is...
Orbital angular momentum exchange in cylindrical-lens mode converters
Cylindrical-lens mode converters (Beijersbergen M. W., Allen L., van der Veen H. E. L. O. and Woerdman J. P. 1993 Opt. Commun. 96 123-32) are used to transform between Hermite-Gaussian and...
Orbital angular momentum, optical spanners, and rotational frequency shift
Light possesses both spin and orbital angular momentum. Whereas the spin component arises from the spin of individual photons and is associated with circular polarization, the orbital component...
Construction of a database of benzene biological monitoring
Pople, J.E., Ball, R.L., Padgett, M.J., Aston, J.P.
Biological monitoring of occupational exposure to benzene has been conducted in the petroleum, steel and chemical industries. The urinary benzene-specific biomarker, S-phenylmercapturic acid (PMA),...
Defining the trapping limits of holographical optical tweezers
Sinclair, G., Jordan, P., Leach, J., Padgett, M.J., Cooper, J.
We report on the limitations of using a spatial light modulator (SLM) within optical tweezers to produce both lateral and axial displacements. We find that lateral displacements of optical traps are...
Classic-fractal eigenmodes of unstable canonical resonators
Watterson, C.M.G., Padgett, M.J., Courtial, J.
It was recently shown that intensity cross-sections through the eigenmodes of canonical unstable resonators with polygonal apertures can have the statistical scaling behaviour of fractals. Here we...
Free-space information transfer using light beams carrying orbital angular momentum
Gibson, G., Courtial, J., Padgett, M.J., Vasnetsov, M., Pas'ko, V., Barnett, S.M., ...
We demonstrate the transfer of information encoded as orbital angular momentum (OAM) states of a light beam. The transmitter and receiver units are based on spatial light modulators, which prepare or...
Three-dimensional optical trapping of partially silvered silica microparticles
Jordan, P., Cooper, J., Mcnay, G., Docherty, F.T., Smith, W.E., Sinclair, G., ...
We demonstrate three-dimensional trapping of micrometer- diameter silica particles, partially coated with silver, within conventional optical tweezers. Although metallic particles are usually...
Laser beams: knotted threads of darkness
Leach, J., Dennis, M.R., Courtial, J., Padgett, M.J.
Dark lines within a laser beam can be manipulated to form stable vortex knots. Destructive interference may lead to complete cancellation when light waves travelling in different directions cross,...
Observation of the vortex structure of a non-integer vortex beam
Leach, J., Yao, E., Padgett, M.J.
An optical beam with an e(i/phi) phase structure carries an orbital angular momentum of lh per photon. For integer l values, the phase fronts of such beams form perfect helices with a single...
The mechanism for energy transfer in the rotational frequency shift of a light beam
It is well known that when a light beam containing angular momentum is rotated about the propagation axis it is shifted in frequency. The magnitude of the shift is equal to the angular momentum per...
Sinclair, G., Leach, J., Jordan, P., Gibson, G., Yao, E., Laczik, Z.J., ...
Phase-hologram patterns that can shape the intensity distribution of a light beam in several planes simultaneously can be calculated with an iterative Gerchberg-Saxton algorithm [T. Haist et al.,...
3D manipulation of particles into crystal structures using holographic optical tweezers
Leach, J., Sinclair, G., Jordan, P., Courtial, J., Padgett, M.J., Cooper, J., ...
We have developed holographic optical tweezers that can manipulate many particles simultaneously in three dimensions in order to create micro-crystal structures that extend over many tens of microns....
Matrix formulation for the propagation of light beams with orbital and spin angular momenta
Allen, L., Courtial, J., Padgett, M.J.
Jones matrices describe the polarization, or spin angular momentum, of a light beam as it passes through an optical system. We devise an equivalent of the Jones matrix formulation for light...
The rate of electromagnetic energy flow per unit area, the Poynting vector, is defined and discussed in all books of electromagnetism. The vector and its associated linear momentum density is,...
Response to Question #79. Does a plane wave carry spin angular momentum?
No abstract available.
A computer-generated hologram is used to form an optical beam with a localized intensity null at its focus. The beam is a superposition of two Laguerre-Gaussian modes that are phased so that they...
Mueller matrix error correction for a fringe-free interferometry system
Begbie, M.L., Sibbett, W., Padgett, M.J.
We present an automated surface profiling system based on a shearing interferometer, in which precise measurement of the polarization states eliminates fringe ambiguity. A full error correction based...
Optically controlled three-dimensional rotation of microscopic objects
Bingelyte, V., Leach, J., Courtial, J., Padgett, M.J.
An approach of optically controlled three-dimensional rotation of microscopic objects was studied. A spatially light modulator was used to create a pair of closely separated optical traps holding...
Holographic generation and orbital angular momentum of high-order mathieu beams
Chavez-Cerda, S., Padgett, M.J., Allison, I., New, G.H.C., Gutierrez-Vega, J.C., O'Neil, A.T., ...
We report the first experimental generation of high-order Mathieu beams and confirm their propagation invariance over a limited range. In our experiment we use a computer-generated phase hologram....
Generation of self-reproducing fractal patterns using a multiple imaging system with feedback
We present a simple optical system for producing self-similar fractal patterns. The key component comprises three adjacent lenses, which form multiple images of a pattern displayed on a monitor. The...
Within a ray-optical approximation we show that there is a limit to the orbital angular momentum per unit energy that can be focused onto a small particle. This limit depends solely on the geometry...
A novel mechanism is proposed for the generation of self-similar structure over a limited range of length scales. Our mechanism, which we call the monitor-outside-a-monitor effect, comprises repeated...
Fractal generation using optical feedback with incoherent gain
Forrester, A., Courtial, J., Padgett, M.J.
We present an optical system for the spontaneous generation of self-similar fractal patterns. The system configuration is that of a ring cavity containing a lens array to form multiple, but laterally...
Performance of a rotating aperture for spinning and orienting objects in optical tweezers
Forrester, A., Courtial, J., Padgett, M.J.
The spinning of asymmetric objects trapped within optical tweezers that have a rotating rectangular aperture inserted into the trapping laser beam is characterized. The measured maximum rotation...
Why are the eigenmodes of stable laser resonators structurally stable?
Forrester, A., Lonnqvist, M., Padgett, M.J., Courtial, J.
Optical resonators are usually examined wave optically. We consider geometrical imaging in stable canonical resonators. We show that, with important exceptions related to eigenmode degeneracy, stable...
Two-photon entanglement of orbital angular momentum states
Franke-Arnold, S., Barnett, S.M., Padgett, M.J., Allen, L.
We investigate the orbital angular momentum correlation of a photon pair created in a spontaneous parametric down-conversion process. We show how the conservation of the orbital angular momentum in...
Garces-Chavez, V., McGloin, D., Padgett, M.J., Dultz, W., Schmitzer, H., Dholakia, K.
We observe the spinning and orbital motion of a microscopic particle trapped within a multiringed light beam that arises from the transfer of the spin and orbital components of the light's angular...
Simplified measurement of the orbital angular momentum of single photons
Haiqing, Wei, Xin, Xue, Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., ...
We describe a simplification of a recent approach for sorting photons according to their orbital angular momentum (OAM) [Leach et al., Phys. Rev. Lett. 88 (2002) 257901]. The original cascade of...
Fractals in pixellated video feedback
Leach, J., Padgett, M.J., Courtial, J.
Using experiments and computer simulations, we show that video feedback with a pixel-based monitor can lead to self-similar stationary patterns. We found an astonishing variety of such patterns,...
Leach, J., Courtial, J., Skeldon, K., Barnett, S.M., Franke-Arnold, S., Padgett, M.J.
We propose interferometric methods capable of measuring either the total angular momentum, or simultaneously measuring the spin and orbital angular momentum of single photons. This development...
Measuring the orbital angular momentum of a single photon
Leach, J., Padgett, M.J., Barnett, S.M., Franke-Arnold, S., Courtial, J.
We propose an interferometric method for measuring the orbital angular momentum of single photons. We demonstrate its viability by sorting four different orbital angular momentum states, and are thus...
Aberrations introduced by a lens made from a birefringent material
Lesso, J.P., Duncan, A.J., Sibbett, W., Padgett, M.J.
We incorporate an algorithm for ray tracing in birefringent media into a full ray-tracing package based on the Mathematica software application. To validate the package, we compare the calculated and...
Lights, action: optical tweezers
Optical tweezers were first realized 15 years ago by Arthur Ashkin and co-workers at the Bell Telephone Laboratories. Since that time there has been a steady stream of developments and applications,...
Preface: Optical tweezers in a new light
Molloy, J.E., Dholakia, K., Padgett, M.J.
Optical tweezers were invented in the mid-1980s by Arthur Ashkin and co-workers at the Bell Telephone Laboratories. Since then there has been a steady stream of developments and applications,...
A compact fluorescence spectroscopic tool for cancer detection
Nadeau, V., Hamdan, K., Hewett, J., Makaryceva, J., Tait, I., Cuschieri, A., ...
We describe a compact fluorescence spectroscopic tool for in vivo point monitoring of aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence and autofluorescence, as a non-invasive...
Real-time measurement of volcanic H2S and SO2 concentrations by UV spectroscopy
O'Dwyer, M., Padgett, M.J., McGonigle, A.J.S., Oppenheimer, C., Inguaggiato, S.
Sulphur speciation in volcanic gases acts as a major redox buffer, and H2S/SO2 ratios represent a valuable indicator of magmatic conditions and interactions between magmatic and hydrothermal fluids....
A multimode fibre-coupled compact optical wavelength meter based on Wollaston prisms
We present a compact, portable, and mechanically robust instrument for measuring optical wavelength based on an arrangement of four Wollaston prisms that forms spatially localised fringes in a plane...
Wollaston prism-based digital laser wavelength meter
We present a device designed to measure laser output wavelength and based on Wollaston prisms and barium borate (BBO) crystal polarizers. The arrangement generates a localized fringe plane...
Axial and lateral trapping efficiency of Laguerre-Gaussian modes in inverted optical tweezers
Within inverted optical tweezers we measure both the lateral and axial trapping efficiency obtained with Gaussian and high-order Laguerre-Gaussian beams. Our results confirm that, for larger...
Intrinsic and extrinsic nature of the orbital angular momentum of a light beam
O'Neil, A.T., MacVicar, I., Allen, L., Padgett, M.J.
We explain that, unlike the spin angular momentum of a light beam which is always intrinsic, the orbital angular momentum may be either extrinsic or intrinsic. Numerical calculations of both spin and...
Rotational control within optical tweezers by use of a rotating aperture
We demonstrate a simplified method of rotational control of objects trapped within optical tweezers that does not require high-order modes, interferometric precision, or computer-controlled optical...
We report a new mechanism for trapping metallic particles in inverted optical tweezers. The particles are loosely confined, in three dimensions, to an annular region just below the beam waist where...
Transfer of orbital angular momentum to metal particles confined using optical tweezers
Using Laguerre-Gaussian beams in an inverted optical tweezers geometry we observe that silver particles, 2 mu m in diameter, are confined to an annulus around the outside of the beam. This annulus is...
Orbital angular momentum exchange in cylindrical-lens mode converters
Cylindrical-lens mode converters (Beijersbergen M. W., Allen L., van der Veen H. E. L. O. and Woerdman J. P. 1993 Opt. Commun. 96 123-32) are used to transform between Hermite-Gaussian and...
Orbital angular momentum, optical spanners, and rotational frequency shift
Light possesses both spin and orbital angular momentum. Whereas the spin component arises from the spin of individual photons and is associated with circular polarization, the orbital component...
Construction of a database of benzene biological monitoring
Pople, J.E., Ball, R.L., Padgett, M.J., Aston, J.P.
Biological monitoring of occupational exposure to benzene has been conducted in the petroleum, steel and chemical industries. The urinary benzene-specific biomarker, S-phenylmercapturic acid (PMA),...
Defining the trapping limits of holographical optical tweezers
Sinclair, G., Jordan, P., Leach, J., Padgett, M.J., Cooper, J.
We report on the limitations of using a spatial light modulator (SLM) within optical tweezers to produce both lateral and axial displacements. We find that lateral displacements of optical traps are...
Classic-fractal eigenmodes of unstable canonical resonators
Watterson, C.M.G., Padgett, M.J., Courtial, J.
It was recently shown that intensity cross-sections through the eigenmodes of canonical unstable resonators with polygonal apertures can have the statistical scaling behaviour of fractals. Here we...
Free-space information transfer using light beams carrying orbital angular momentum
Gibson, G., Courtial, J., Padgett, M.J., Vasnetsov, M., Pas'ko, V., Barnett, S.M., ...
We demonstrate the transfer of information encoded as orbital angular momentum (OAM) states of a light beam. The transmitter and receiver units are based on spatial light modulators, which prepare or...
Three-dimensional optical trapping of partially silvered silica microparticles
Jordan, P., Cooper, J., Mcnay, G., Docherty, F.T., Smith, W.E., Sinclair, G., ...
We demonstrate three-dimensional trapping of micrometer- diameter silica particles, partially coated with silver, within conventional optical tweezers. Although metallic particles are usually...
Laser beams: knotted threads of darkness
Leach, J., Dennis, M.R., Courtial, J., Padgett, M.J.
Dark lines within a laser beam can be manipulated to form stable vortex knots. Destructive interference may lead to complete cancellation when light waves travelling in different directions cross,...
Observation of the vortex structure of a non-integer vortex beam
Leach, J., Yao, E., Padgett, M.J.
An optical beam with an e(i/phi) phase structure carries an orbital angular momentum of lh per photon. For integer l values, the phase fronts of such beams form perfect helices with a single...
The mechanism for energy transfer in the rotational frequency shift of a light beam
It is well known that when a light beam containing angular momentum is rotated about the propagation axis it is shifted in frequency. The magnitude of the shift is equal to the angular momentum per...
Sinclair, G., Leach, J., Jordan, P., Gibson, G., Yao, E., Laczik, Z.J., ...
Phase-hologram patterns that can shape the intensity distribution of a light beam in several planes simultaneously can be calculated with an iterative Gerchberg-Saxton algorithm [T. Haist et al.,...
3D manipulation of particles into crystal structures using holographic optical tweezers
Leach, J., Sinclair, G., Jordan, P., Courtial, J., Padgett, M.J., Cooper, J., ...
We have developed holographic optical tweezers that can manipulate many particles simultaneously in three dimensions in order to create micro-crystal structures that extend over many tens of microns....