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676 Works

Enhanced absorption in optically thin solar cells by scattering from embedded dielectric nanoparticles

James R. Nagel & Michael A. Scarpulla
We present a concept for improving the efficiency of thin-film solar cells via scattering from dielectric particles. The particles are embedded directly within the semiconductor absorber material with sizes on the order of one wavelength. Importantly, this geometry is fully compatible with the use of an anti-reflective coating (ARC) to maximize light capture. The concept is demonstrated through finite-difference time domain (FDTD) simulations of spherical SiO2 particles embedded within a 1.0 µm layer of crystalline...

Enhanced absorption in optically thin solar cells by scattering from embedded dielectric nanoparticles

James R. Nagel & Michael A. Scarpulla
We present a concept for improving the efficiency of thin-film solar cells via scattering from dielectric particles. The particles are embedded directly within the semiconductor absorber material with sizes on the order of one wavelength. Importantly, this geometry is fully compatible with the use of an anti-reflective coating (ARC) to maximize light capture. The concept is demonstrated through finite-difference time domain (FDTD) simulations of spherical SiO2 particles embedded within a 1.0 µm layer of crystalline...

Synthesis and display of dynamic holographic 3D scenes with real-world objects

Melania Paturzo, Pasquale Memmolo, Andrea Finizio, Risto Näsänen, Thomas J. Naughton & Pietro Ferraro
A 3D scene is synthesized combining multiple optically recorded digital holograms of different objects. The novel idea consists of compositing moving 3D objects in a dynamic 3D scene using a process that is analogous to stop-motion video. However in this case the movie has the exciting attribute that it can be displayed and observed in 3D. We show that 3D dynamic scenes can be projected as an alternative to complicated and heavy computations needed to...

Synthesis and display of dynamic holographic 3D scenes with real-world objects

Melania Paturzo, Pasquale Memmolo, Andrea Finizio, Risto Näsänen, Thomas J. Naughton & Pietro Ferraro
A 3D scene is synthesized combining multiple optically recorded digital holograms of different objects. The novel idea consists of compositing moving 3D objects in a dynamic 3D scene using a process that is analogous to stop-motion video. However in this case the movie has the exciting attribute that it can be displayed and observed in 3D. We show that 3D dynamic scenes can be projected as an alternative to complicated and heavy computations needed to...

Superfast phase-shifting method for 3-D shape measurement

Song Zhang, Daniel Van Der Weide & James Oliver
Recently introduced DLP Discovery technology allows for tens of kHz binary image switching, which has great potential for superfast 3-D shape measurement. This paper presents a system that realizes 3-D shape measurement by using a DLP Discovery technology to switch binary structured patterns at very high frame rates. The sinusoidal fringe patterns are generated by properly defocusing the projector. Combining this approach with a phase-shifting method, we achieve an unprecedented rate for 3-D shape measurement:...

Superfast phase-shifting method for 3-D shape measurement

Song Zhang, Daniel Van Der Weide & James Oliver
Recently introduced DLP Discovery technology allows for tens of kHz binary image switching, which has great potential for superfast 3-D shape measurement. This paper presents a system that realizes 3-D shape measurement by using a DLP Discovery technology to switch binary structured patterns at very high frame rates. The sinusoidal fringe patterns are generated by properly defocusing the projector. Combining this approach with a phase-shifting method, we achieve an unprecedented rate for 3-D shape measurement:...

Multi-projection of lenticular displays to construct a 256-view super multi-view display

Yasuhiro Takaki & Nichiyo Nago
A new super multi-view (SMV) display system that enables the number of views to be increased is proposed. All three-dimensional (3D) images generated by multiple multi-view flat-panel displays are superimposed on a common screen using a multi-projection system. The viewing zones of the flat-panel 3D display are produced in the pupils of the projection lenses and then imaged to the observation space by a screen lens. Sixteen flat-panel 3D displays having 16 views were used...

Multi-projection of lenticular displays to construct a 256-view super multi-view display

Yasuhiro Takaki & Nichiyo Nago
A new super multi-view (SMV) display system that enables the number of views to be increased is proposed. All three-dimensional (3D) images generated by multiple multi-view flat-panel displays are superimposed on a common screen using a multi-projection system. The viewing zones of the flat-panel 3D display are produced in the pupils of the projection lenses and then imaged to the observation space by a screen lens. Sixteen flat-panel 3D displays having 16 views were used...

ITO-free large-area organic solar cells

Seungkeun Choi, William J. Potscavage & Bernard Kippelen
We report on large-area pentacene / C60 organic solar cells in which indium-tin-oxide (ITO) is replaced with a conductive polymer electrode and a 5 μm-thick metal grid is used to reduce resistive power losses. The performance of cells with the polymer electrode was compared with that of pentacene / C60 devices using ITO as the transparent electrode. For large-area devices (7.3 cm2) on glass substrates with an integrated metal grid, the performance of a device...

ITO-free large-area organic solar cells

Seungkeun Choi, William J. Potscavage & Bernard Kippelen
We report on large-area pentacene / C60 organic solar cells in which indium-tin-oxide (ITO) is replaced with a conductive polymer electrode and a 5 μm-thick metal grid is used to reduce resistive power losses. The performance of cells with the polymer electrode was compared with that of pentacene / C60 devices using ITO as the transparent electrode. For large-area devices (7.3 cm2) on glass substrates with an integrated metal grid, the performance of a device...

Vortex solitons in lasers with feedback

P. V. Paulau, D. Gomila, P. Colet, N. A. Loiko, N. N. Rosanov, T. Ackemann & W. J. Firth
We report on the existence, stability and dynamical properties of two-dimensional self-localized vortices with azimuthal numbers up to 4 in a simple model for lasers with frequency-selective feedback. We build the full bifurcation diagram for vortex solutions and characterize the different dynamical regimes. The mathematical model used, which consists of a laser rate equation coupled to a linear equation for the feedback field, can describe the spatiotemporal dynamics of broad area vertical cavity surface emitting...

Optically switchable, rapidly relaxing cholesteric liquid crystal reflectors

Uladzimir A. Hrozhyk, Svetlana V. Serak, Nelson V. Tabiryan, Timothy J. White & Timothy J. Bunning
Reversible, fast, all-optical switching of the reflection of a cholesteric liquid crystal (CLC) is demonstrated in a formulation doped with push-pull azobenzene dyes. The reflection of the photosensitive CLC compositions is optically switched by exposure to 488 and 532 nm CW lasers as well as ns pulsed 532 nm irradiation. Laser-directed optical switching of the reflection of the CLC compositions occurs rapidly, within a few hundred milliseconds for the CW laser lines examined here. Also...

Optically switchable, rapidly relaxing cholesteric liquid crystal reflectors

Uladzimir A. Hrozhyk, Svetlana V. Serak, Nelson V. Tabiryan, Timothy J. White & Timothy J. Bunning
Reversible, fast, all-optical switching of the reflection of a cholesteric liquid crystal (CLC) is demonstrated in a formulation doped with push-pull azobenzene dyes. The reflection of the photosensitive CLC compositions is optically switched by exposure to 488 and 532 nm CW lasers as well as ns pulsed 532 nm irradiation. Laser-directed optical switching of the reflection of the CLC compositions occurs rapidly, within a few hundred milliseconds for the CW laser lines examined here. Also...

Vortex solitons in lasers with feedback

P. V. Paulau, D. Gomila, P. Colet, N. A. Loiko, N. N. Rosanov, T. Ackemann & W. J. Firth
We report on the existence, stability and dynamical properties of two-dimensional self-localized vortices with azimuthal numbers up to 4 in a simple model for lasers with frequency-selective feedback. We build the full bifurcation diagram for vortex solutions and characterize the different dynamical regimes. The mathematical model used, which consists of a laser rate equation coupled to a linear equation for the feedback field, can describe the spatiotemporal dynamics of broad area vertical cavity surface emitting...

Spatial filtering technique to image and measure two-dimensional near-forward scattering from single particles

Matthew J. Berg, Steven C. Hill, Gorden Videen & Kristan P. Gurton
This work describes the design and use of an optical apparatus to measure the far-field elastic light-scattering pattern for a single particle over two angular-dimensions. A spatial filter composed of a mirror with a small through-hole is used to enable collection of the pattern uncommonly close to the forward direction; to within tenths of a degree. Minor modifications of the design allow for the simultaneous measurement of a particle’s image along with its two-dimensional scattering...

Spatial filtering technique to image and measure two-dimensional near-forward scattering from single particles

Matthew J. Berg, Steven C. Hill, Gorden Videen & Kristan P. Gurton
This work describes the design and use of an optical apparatus to measure the far-field elastic light-scattering pattern for a single particle over two angular-dimensions. A spatial filter composed of a mirror with a small through-hole is used to enable collection of the pattern uncommonly close to the forward direction; to within tenths of a degree. Minor modifications of the design allow for the simultaneous measurement of a particle’s image along with its two-dimensional scattering...

RECIST versus volume measurement in medical CT using ellipsoids of known size

Zachary H. Levine, Bruce R. Borchardt, Nolan J. Brandenburg, Charles W. Clark, Bala Muralikrishnan, Craig M. Shakarji, Joseph J. Chen & Eliot L. Siegel
Two hundred eighty three uniaxial ellipsoids with sizes from 4 mm to 11 mm were measured with a coordinate measuring matching (CMM) and also scanned using a medical computed tomography (CT) machine. Their volumes were determined by counting voxels over a threshold, as well as using equivalent volumes from the length given by the RECIST 1.1 criterion (Response Evaluation Criteria in Solid Tumors). The volumetric measurements yield an order of magnitude reduction in residuals compared...

RECIST versus volume measurement in medical CT using ellipsoids of known size

Zachary H. Levine, Bruce R. Borchardt, Nolan J. Brandenburg, Charles W. Clark, Bala Muralikrishnan, Craig M. Shakarji, Joseph J. Chen & Eliot L. Siegel
Two hundred eighty three uniaxial ellipsoids with sizes from 4 mm to 11 mm were measured with a coordinate measuring matching (CMM) and also scanned using a medical computed tomography (CT) machine. Their volumes were determined by counting voxels over a threshold, as well as using equivalent volumes from the length given by the RECIST 1.1 criterion (Response Evaluation Criteria in Solid Tumors). The volumetric measurements yield an order of magnitude reduction in residuals compared...

Programmable photonic crystal nanobeam cavities

Ian W. Frank, Parag B. Deotare, Murray W. McCutcheon & Marko Lončar
We present dynamically reconfigurable photonic crystal nanobeam cavities, operating at ~1550 nm, that can be continuously and reversibly tuned over a 9.5 nm wavelength range. The devices are formed by two coupled nanobeam cavities, and the tuning is achieved by varying the lateral gap between the nanobeams. An electrostatic force, obtained by applying bias voltages directly to the nanobeams, is used to control the spacing between the nanobeams, which in turn results in tuning of...

Programmable photonic crystal nanobeam cavities

Ian W. Frank, Parag B. Deotare, Murray W. McCutcheon & Marko Lončar
We present dynamically reconfigurable photonic crystal nanobeam cavities, operating at ~1550 nm, that can be continuously and reversibly tuned over a 9.5 nm wavelength range. The devices are formed by two coupled nanobeam cavities, and the tuning is achieved by varying the lateral gap between the nanobeams. An electrostatic force, obtained by applying bias voltages directly to the nanobeams, is used to control the spacing between the nanobeams, which in turn results in tuning of...

Grating couplers for broadside input and output coupling of long-range surface plasmons

Chengkun Chen & Pierre Berini
Metal gratings for in-coupling a Gaussian beam incident from broadside to the long-range surface plasmon polariton (LRSPP) propagating in one direction along a membrane-supported Au slab bounded by air or water are proposed and modeled by the finite-difference time-domain method. Grating couplers for out-coupling the propagating LRSPP into free radiation directed along broadside are also investigated. Short grating designs consisting of a small number of Au bumps yield 15% to 20% in-coupling efficiencies, and about...

Azobenzene liquid crystalline materials for efficient optical switching with pulsed and/or continuous wave laser beams

Uladzimir A. Hrozhyk, Svetlana V. Serak, Nelson V. Tabiryan, Landa Hoke, Diane M. Steeves & Brian R. Kimball
This study compares optical switching capabilities of liquid crystal (LC) materials based on different classes of azobenzene dyes. LCs based on molecules containing benzene rings with nearly symmetrical π-π conjugation respond more efficiently to a cw beam than to a nanosecond laser pulse and maintain the changes induced by the beam for tens of hours. Using azo dye molecules containing two benzene rings with push-pull π-π conjugation we demonstrate high photosensitivity to both a cw...

Grating couplers for broadside input and output coupling of long-range surface plasmons

Chengkun Chen & Pierre Berini
Metal gratings for in-coupling a Gaussian beam incident from broadside to the long-range surface plasmon polariton (LRSPP) propagating in one direction along a membrane-supported Au slab bounded by air or water are proposed and modeled by the finite-difference time-domain method. Grating couplers for out-coupling the propagating LRSPP into free radiation directed along broadside are also investigated. Short grating designs consisting of a small number of Au bumps yield 15% to 20% in-coupling efficiencies, and about...

Azobenzene liquid crystalline materials for efficient optical switching with pulsed and/or continuous wave laser beams

Uladzimir A. Hrozhyk, Svetlana V. Serak, Nelson V. Tabiryan, Landa Hoke, Diane M. Steeves & Brian R. Kimball
This study compares optical switching capabilities of liquid crystal (LC) materials based on different classes of azobenzene dyes. LCs based on molecules containing benzene rings with nearly symmetrical π-π conjugation respond more efficiently to a cw beam than to a nanosecond laser pulse and maintain the changes induced by the beam for tens of hours. Using azo dye molecules containing two benzene rings with push-pull π-π conjugation we demonstrate high photosensitivity to both a cw...

A simple scanless two-photon fluorescence microscope using selective plane illumination

Jonathan Palero, Susana I.C.O. Santos, David Artigas & Pablo Loza-Alvarez
We demonstrate a simple scanless two-photon (2p) excited fluorescence microscope based on selective plane illumination microscopy (SPIM). Optical sectioning capability is presented and depth-resolved imaging of cameleon protein in C. elegans pharyngeal muscle is implemented.

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  • 2010
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