Abstract: In some embodiments, a method to excite a shock wave in a target assembly includes: splitting a pulsed laser beam into a plurality of pulsed laser beams; spatially shaping the plurality of pulsed laser beams into a plurality of concentric pulsed laser rings of different diameters; and adjusting temporal and/or spatial intervals between the concentric pulsed laser rings to substantially match propagation times of a ring-shaped laser-driven shock wave from one ring to the next in a shock propagation layer of the target assembly.

Abstract: A system, method and apparatus for providing pulsed power comprises a trigger comprising a pulse generator and a photonic transmitter and a multi-stage switch comprising a gate driver circuit, the gate driver circuit further comprising a plurality of transistors connected in series and a plurality of driver stages wherein each of the transistors is turned on and off simultaneously by the plurality of driver stages.

Abstract: A semiconductor laser tuned with an acousto-optic modulator. The acousto-optic modulator may generate standing waves or traveling waves. When traveling waves are used, a second acousto-optic modulator may be used in a reverse orientation to cancel out a chirp created in the first acousto-optic modulator. The acousto-optic modulator may be used with standing-wave laser resonators or ring lasers.

Abstract: Certain embodiments are directed to control methods, window controllers, and uninterruptible power supplies for determining tinting instructions for optically switchable windows to reduce power usage at a site during a reduced power event. In some cases, reduced power operations are initiated by a window controller upon receipt of a trigger signal from an uninterruptible power supply sent when it detects a power loss. In some cases, tinting instructions are based on the remaining charge left on the uninterruptible power supply. In some cases, reduced power operations are delayed for a period of time.

Abstract: There is provided an an apparatus for reducing coherence of a laser beam, which apparatus comprises a rectangular chamber having a first, second, and third walls each comprising a reflective inner surface, and a fourth wall comprising a beam splitter. The fourth wall is configured to transmit a portion of the laser beam into the chamber to form an input beam incident upon the first wall. The first wall is configured to reflect the input beam onto the second wall, which is configured to reflect the input beam onto the third wall, which is configured to reflect the input beam onto the fourth wall. The fourth wall is configured to reflect a portion of the input beam to form a further input beam incident upon the first wall and to transmit another portion of the input beam out of the chamber to form an output laser beam.

Abstract: The invention provides a gray level control method for outputting a total gray level during a total period, including: dividing the total period into M unit periods; alternatively outputting a gray level “0” or a selected gray level during each unit period; and integrating the gray levels output during the M unit periods to obtain the total gray level, wherein during each of N successive unit periods of the M unit periods the selected gray level is a first gray level, and during each of the remaining (M?N) unit periods the selected gray level is lower than the first gray level.

Abstract: The present invention provides a method and apparatus for fabricating a grating on a silicon substrate, and the resulting grating device. In some embodiments, the apparatus method includes providing a silicon substrate; growing a diamond layer on the substrate; removing most of the silicon substrate and polishing an obverse face of the silicon to leave a very thin layer of polished silicon on the diamond layer; depositing a stack on the diamond layer, wherein the stack includes a plurality of pairs of dielectric layers on the thin layer of polished silicon, wherein each pair of the plurality of pairs of dielectric layers includes a first layer having a first index of refraction value and a second layer having a second index of refraction value that is different than the first index of refraction value; and forming a diffraction grating on an outer surface of the stack.

Abstract: A phase-modulated optical link and methods are provided to suppress distortions in phase-encoded analog photonic links. The phase-modulated optical link includes a distortion compensation element. The distortion compensation element includes an optical comb generator that is seeded by a phase-encoded optical signal. The methods include generating an optical comb seeded by a portion of a phase-encoded optical signal and isolating desired peaks to be combined with a separate portion of the phase-encoded optical signal.

Abstract: Certain example embodiments of this invention relate to electrochromic (EC) devices, assemblies incorporating electrochromic devices, and/or methods of making the same. More particularly, certain example embodiments of this invention relate to improved EC materials, EC device stacks, high-volume manufacturing (HVM) compatible process integration schemes, and/or high-throughput low cost deposition sources, equipment, and factories.

Abstract: A method for optical chirp-free optical polarization modulation includes dividing a data modulated optical signal into a first optical path and a second optical path, using a Mach-Zehnder intensity modulator in the first optical path for imparting a ? phase difference between adjacent symbols of the data modulated optical signal in the first optical path, adjusting a delay and amplitude of symbols of the data modulated optical signal in the second path so that the symbols in the first path and the symbols in the second path are synchronized and have substantially equal power levels, and combining the first and second optical paths so that symbols from the first and second optical paths are in orthogonal polarizations.

Abstract: Embodiments of the invention provide apparatuses and methods for phase correlated seeding of parametric mixer and for generating coherent frequency combs. The parametric mixer may use two phase-correlated optical waves with different carrier frequencies to generate new optical waves centered at frequencies differing from the input waves, while retaining the input wave coherent properties. In the case when parametric mixer is used to generate frequency combs with small frequency pitch, the phase correlation of the input (seed) waves can be achieved by electro-optical modulator and a single master laser. In the case when frequency comb possessing a frequency pitch that is larger than frequency modulation that can be affected by electro-optic modulator, the phase correlation of the input (seed) waves is achieved by combined use of an electro-optical modulator and injection locking to a single or multiple slave lasers.

Abstract: Recent invention of longitudinally chirped volume Bragg gratings has dramatically changed a design of high power femtosecond lasers. Replacing of bulky pairs of conventional surface gratings with compact and robust chirped volume Bragg gratings for stretching and compression of laser pulses in chirped-pulse-amplification systems enabled decrease of size and weight of those systems by several times. The methods and devices enable substantial increase of stretching time and compression to shorter pulses, enhancement of stretched and compressed beams quality by stationary or dynamic shaping of gratings, and shaping of laser pulses in both temporal and spectral domains.

Abstract: Embodiments of the invention provide apparatuses and methods for phase correlated seeding of parametric mixer and for generating coherent frequency combs. The parametric mixer may use two phase-correlated optical waves with different carrier frequencies to generate new optical waves centered at frequencies differing from the input waves, while retaining the input wave coherent properties. In the case when parametric mixer is used to generate frequency combs with small frequency pitch, the phase correlation of the input (seed) waves can be achieved by electro-optical modulator and a single master laser. In the case when frequency comb possessing a frequency pitch that is larger than frequency modulation that can be affected by electro-optic modulator, the phase correlation of the input (seed) waves is achieved by combined use of an electro-optical modulator and injection locking to a single or multiple slave lasers.

Abstract: A technique for modulating light by an optically addressed, electric charge accumulating spatial light modulator achieves substantially monotonic gray scale response. Embodiments digitally modulate the voltage across a photoreceptive material included in the spatial light modulator. The digital modulation scheme entails illuminating the photoreceptor with a series of light pulses propagating from an LCoS, in which the durations of the light pulses and their positions in time combine to produce binary-weighted equivalent rms voltages on the photoreceptor. The light pulses originate from a light-emitting diode or other switchable light source, and the timing of the light pulses is controlled such that they are emitted only when the associated LCoS is in a stable state. Emitting light pulses while the LCoS is in a stable state avoids non-monotonic behavior.

Abstract: An image processing apparatus, an image processing method, and a program thereof, and a display device are provided, in which reproduction of a secret image from one dispersed image is difficult. A secret image and a reverse image included in at least two types of images are in a relationship of forming image data of an image not correlated with the secret image when luminance values of image data respectively are added pixel by pixel.

Abstract: Compositions capable of simultaneous two-photon absorption and higher order absorptivities are provided. Compounds having a donor-pi-donor or acceptor-pi-acceptor structure are of particular interest, where the donor is an electron donating group, acceptor is an electron accepting group, and pi is a pi bridge linking the donor and/or acceptor groups. The pi bridge may additionally be substituted with electron donating or withdrawing groups to alter the absorptive wavelength of the structure. Also disclosed are methods of generating an excited state of such compounds through optical stimulation with light using simultaneous absorption of photons of energies individually insufficient to achieve an excited state of the compound, but capable of doing so upon simultaneous absorption of two or more such photons. Applications employing such methods are also provided, including controlled polymerization achieved through focusing of the light source(s) used.

Abstract: An apparatus includes an optical train pulse generator for generating continuous optical pulses each having a narrow width; a clock source having a high frequency for triggering the generator and operable as a sampling clock; a digital-to-analog converter DAC for converting an input signal from a digital signal processor, the DAC responsive to the sampling clock; a data modulator responsive to an amplified output from the DAC to modulate the continuous optical pulses from the train pulse generator; and a filter for removing higher frequency harmonics from the modulated continuous optical pulses out of the data modulator.

Abstract: Illumination subsystems of a metrology system, metrology systems, and methods for illuminating a specimen for metrology measurements are provided.

Abstract: A method, device and computer program are detailed for modulating write light. For a plurality of pixel locations of an electro-optic layer of an optical write valve and across each of a plurality of consecutive frames, a set of pixel data bits is modulated across a first and a second pulse width period of the frame. The first and second pulse width periods, and adjacent pulse periods of sequential frames, are separated from one another by a pulse-off period that is at least equal to a response time of the electro-optic layer during which no bits are modulated. Separately in each frame, write light is output from each of the plurality of pixel locations according to the modulated pixel data bits in the frame. In an embodiment, the set of pixel data bits are modulated by applying a voltage at a pixel location of the electro-optic layer in synchronism with illuminating a light source that illuminates that pixel location.

Abstract: An apparatus includes an optical train pulse generator for generating continuous optical pulses each having a narrow width; a clock source having a high frequency for triggering the generator and operable as a sampling clock; a digital-to-analog converter DAC for converting an input signal from a digital signal processor, the DAC responsive to the sampling clock; a data modulator responsive to an amplified output from the DAC to modulate the continuous optical pulses from the train pulse generator; and a filter for removing higher frequency harmonics from the modulated continuous optical pulses out of the data modulator.

Abstract: Providing a soliton mode-locked solid-state laser that includes a resonator, a first end of which is formed of a semiconductor saturable absorption mirror, a solid-state laser medium, a negative group velocity dispersion compensator for compensating for group velocity dispersion within the resonator, and an excitation optical system that outputs excitation light for exciting the solid-state laser medium, and oscillates soliton pulse laser light with a repetition frequency of not less than 1 GHz, an intensity modulator that includes a waveguide electrooptic modulator for modulating intensity of the soliton pulse laser light and a driver for applying a voltage to the waveguide electrooptic modulator according to desired information, and a nonlinear optical element for converting the intensity-modulated soliton pulse laser light to a second harmonic wave.

Abstract: A projection apparatus includes a light source for emitting a light including at least two different wavelengths; a light source control circuit for controlling a light source to emit the light as pulse emissions with a pulse modulation control; at least two spatial light modulators each comprises plurality of pixel elements are arranged in an array; a spatial light modulator control circuit for selectively controlling a modulation state of the respective pixel elements in each of the spatial light modulators in accordance with image data corresponding to the respective pixel elements; and the light source control circuit controls the light source so that a starting time of a pulse emission period of the pulse emissions of at least one of the wavelengths emitted from the light source is different from a modulation control timing of the pixel element of the spatial light modulator.

Abstract: The invention relates to electro-optic displays and methods for driving such displays. The invention provides (i) electrochromic displays with solid charge transport layers; (ii) apparatus and methods for improving the contrast and reducing the cost of electrochromic displays; (iii) apparatus and methods for sealing electrochromic displays from the outside environment and preventing ingress of contaminants into such a display; and (iv) methods for adjusting the driving of electro-optic displays to allow for environmental and operating parameters.

Abstract: The invention relates to a method and an arrangement for measuring power for an optical user signal transmitted via an optical fiber by converting the transmitted optical user signal into a pulsed optical measurement signal, the pulse repetition rate of which is dependent on the power of the transmitted optical user signal, and evaluating the pulse repetition rate of the converted optical measurement signal in order to ascertain the power of the optical user signal transmitted via the optical fiber.

Abstract: A tunable pulsed laser source comprising a seed source adapted to generate a seed signal and an optical circulator. The optical circulator includes a first port coupled to the seed source, a second port, and a third port. The laser source also includes an amplitude modulator characterized by a first side and a second side. The first side is coupled to the second port of the optical circulator. The laser source further includes a first optical amplifier characterized by an input end and a reflective end including a spectral-domain reflectance filter. The input end is coupled to the second side of the amplitude modulator. Moreover, the laser source includes a second optical amplifier coupled to the third port of the optical circulator.

Abstract: An electro-optical device includes a controller, a reference current source, a correction current source, a combining unit, and an electro-optical element. The controller generates a reference current control signal defining a first period during which a reference current is output, and a correction current control signal defining a second period during which a correction current is output, the second period being shorter than the first period. The reference current source generates the reference current based on the reference current control signal. The correction current source generates the correction current based on the correction current control signal. The combining unit combines the reference current and the correction current to generate a driving current. The electro-optical element emits an amount of light corresponding to the driving current.

Abstract: A polarization stabilizing device and method based on controlling the phase retardations of a pair of variable rotators with an optically interposed quarter-wave plate, with a controller such that the first of the variable rotators has its phase retardation switched between first and second values whenever the phase retardation of the second of the variable rotators reaches an upper or a lower limit. The upper and lower limits of the second rotator and the first and second values of the first rotator are chosen so that discontinuities in the power of the output optical radiation are avoided when the first variable rotator is switched, thereby providing endless polarization stabilization using rotators that themselves may have limited retardation ranges.

Abstract: A laser projection device suitable for displaying full color images is disclosed. The LPD includes a variety of techniques for modulating laser beams produced by one or more lasers with image data to controllably produce the image using a modified raster scan.

Abstract: Upon predetermined mark image measurement, the timing signal is adjusted to obtain a required correction amount for a scan magnification of the modulated light in a measurement range of the predetermined mark image measurement, while, upon regular image forming operation, the timing signal is adjusted to obtain the required correction amount for the scan magnification of the modulated light in the entire scanning range of the modulated light for regular image forming operation.

Abstract: Techniques for producing an optical broadband frequency sweep or chirp, include generating a narrowband frequency chirp and a frequency-shifted replica. The narrowband chirp has an optical carrier frequency, a pulse duration and a pulse bandwidth. A frequency-shifted replica is generated by frequency shifting the narrowband chirp by a frequency shift. Adding the frequency-shifted replica after a start of the narrowband chirp by a delay generates a broadband frequency chirp. Alternatively, the frequency-shifted replica is generated by frequency shifting a constant frequency pulse, and modulating the frequency-shifted pulse to generate narrowband chirps that are added to form the broadband chirp.

Abstract: A light modulation type photointerrupter includes: a light source that emits a light pulse to a transit area where an object transits; a driving circuit that drives the light source to emit the light pulse; a photoreceptor that converts the light pulse from the transit area into a pulse current and outputs the pulse current; an integrating circuit that integrates a pulse signal resulting from the pulse current and outputs a result of the integration, the integrating circuit having different time constants at a rise and at a fall of the pulse signal; and a detecting circuit that detects, based upon the output from the integrating circuit, presence or absence of the object in the transit area. The light source is driven to emit a pulse, which reduces the loss of power in the light emitter and the consumption of the current.

Abstract: Disclosed are a light modulation apparatus including a liquid crystal device; and a polarizing plate disposed in an optical path of light made incident on said liquid crystal device; wherein said liquid crystal device is of a guest-host type using a negative type liquid crystal as a host material, an image pickup apparatus using the light modulation apparatus, and methods of driving the light modulation apparatus and image pickup apparatus.

Abstract: An apparatus and method generating an optical pulse of picosecond class (having a high duty ratio), which accurately and stably operates at an arbitrary repetition frequency, has a high OSNR, and is not restricted by an RF modulation frequency, are provided. New modulation spectrum components are generated by performing phase modulation for light output from a single wavelength laser light source with an optical phase modulator. The phases of the modulation spectrum components are aligned by a phase adjuster, so that a pulse wave in a time domain is generated.

Abstract: An optical sampling method and apparatus are provided for modulating an optical signal using a first electroabsorption modulator (EAM) driven by a sinusoidal RF voltage signal to provide substantially jitter free temporal gating of the optical signal. The gated optical signal from the first EAM is routed through a second EAM to provide an optical output signal having a reduced repetition rate. The second EAM is driven using an electrical pulse train having a repetition rate that is a subharmonic of the frequency of the sinusoidal RF voltage signal driving the first EAM.

Abstract: A first optical waveguide, a second optical waveguide, a first electrode, and a second electrode are integrated on a substrate. An optical modulator is provided with a clock signal generator for generating an RZ signal by applying a clock signal to either the first or second electrode, and an NRZ data signal generator for supplying an NRZ data signal to the remaining electrode. Thus, the space required by the optical modulator is reduced while tolerance of the same is improved, thus reducing costs for constructing the optical modulator.

Abstract: A bimorphic polymeric photomechanical actuator, in one embodiment using polyvinylidene fluoride (PVDF) as a photosensitive body, transmitting light over fiber optic cables, and controlling the shape and pulse duration of the light pulse to control movement of the actuator. Multiple light beams are utilized to generate different ranges of motion for the actuator from a single photomechanical body and alternative designs use multiple light beams and multiple photomechanical bodies to provide controlled movement. Actuator movement using one or more ranges of motion is utilized to control motion to position an actuating element in three dimensional space.

Abstract: A system and method for addressing and synchronizing a spatial light modulator (SLM) device and a scrolling color recovery (SCR) illumination system. This method applies all the colors to a single SLM simultaneously and recaptures light rejected by the color filters. The recaptured light is reapplied to the color filters and, if passed by the color filter, directed to the SLM. The SCR concept requires multiple colors to be imaged on to an SLM array simultaneously. As the color bands scroll across the SLM, the data applied to elements of the SLM changes to remain appropriate for the color being received by that element. The data applied to the SLM elements may be loaded into the SLM by reset ground with each reset group load delayed by a skew time relative to the previous group.

Abstract: A method of generating a pulse width modulated (PWM) signal receives digital demand data comprising at least one more significant bit and at least one less significant bit. The PWM signal comprises a sequence of one or more frames, each frame comprising a plurality of PWM pulses whose duty cycle is substantially governed by the at least one more significant bit. At least one of its PWM pulses is selected to have its duty cycle modified in response to the at least one less significant bit. Each of the at least one less significant bit uniquely mapping onto the at least one selected PWM pulse of the frame. An apparatus operable according to this method includes an optical attenuator whose optical attenuation is dependent upon its temperature and in which the temperature and, hence, the attenuation is controlled using the above PWM signal.

Abstract: A device for multiple row addressing is driven with pulse patterns based on sets of 8 (or more) orthogonal functions which have a less varying frequency content than pulse patterns based on a set of 8 Walsh functions. Mutually orthogonal signals are obtained from at least two types of the orthogonal functions having four elementary units of time. Within the four elementary units of time, one pulse each unit of time has a polarity which is different from the plurality of the other pulses.

Abstract: A pulse shaping apparatus for shaping an input optical pulse into an output optical pulse having substantially constant optical power, includes a modulator that acts upon the input optical pulse in response to a control signal. A sampling unit samples a portion of the input or output pulse and generates a sample signal that corresponds to the optical power of the input or output optical pulse. In a preferred embodiment, the sampling unit includes a power splitter that splits off sample portion of the input or output pulse, and directs the sample portion to the photodetector which generates the sample signal. Processing of the sample signal may be performed in either an analog or digital form.

Abstract: There is provided a complex frequency response filter providing a frequency response having a desired shape. A first complex frequency response filter includes a first and a second reflecting surfaces defining a resonant cavity therebetween. Each of the reflecting surfaces respectively has a predetermined surface finish providing a given reflectivity, therefore providing resonances with a predetermined shaped frequency response of a predetermined amplitude and of a predetermined periodicity. Those frequency responses can then be summed to generate an arbitrarily complex spectral response. In another embodiment, the complex frequency response filter includes a transmission medium and a first and a second reflecting surfaces defining a resonant cavity therebetween.

Abstract: Disclosed are a light modulation apparatus including a liquid crystal device; and a polarizing plate disposed in an optical path of light made incident on said liquid crystal device; wherein said liquid crystal device is of a guest-host type using a negative type liquid crystal as a host material, an image pickup apparatus using the light modulation apparatus, and methods of driving the light modulation apparatus and image pickup apparatus.

Abstract: A method and apparatus for information modulation for impulse radios are presented in both single-tone and pulse stream configurations. The modulation techniques include combinations of amplitude and phase modulation. The modulation techniques include both digital and analog schemes, including baseband on/off keying modulation, wavelet on/off keying modulation, pulse-position modulation, and FM modulation. Techniques for varying the modulation rate are also provided. Additionally, harmonics impulse ratio configurations are presented to take advantage of the modulation techniques.

Abstract: A display system (10) comprises a digital micromirror device (DMD) (24) controlled by a driver circuit (30) responsive to sequences of pulse width segments formed by a processor (31). The processor (31) increases the pixel brightness by actuating selected pulses such that within a first range of brightness levels between first and second pixel brightness boundaries, a first large-duration pulse element becomes actuated to reach the second pixel brightness boundary, and within a second range of pixel brightness levels between second and third pixel brightness boundaries, the first large duration pulse element remains actuated. Upon reaching the third pixel brightness boundary, a second large duration pulse element now becomes actuated with the first large duration pulse element remaining actuated. Forming the pulse width segments in this manner serves to reduce motion contouring.

Abstract: An electroabsorption modulator comprises a tandem arrangement of a conventional electroabsorption (EA) modulator element and a phase modulator element. The EA modulator element is driven by the digital data signal and the phase modulator is driven by a chirp tuning control signal, such as the complement of the data signal. By controlling the amplitude and/or bias of the chirp tuning control signal, the frequency chirp of the intensity-modulated output signal from the EA modulator element can be controlled.

Abstract: Optical pulses at a given repetition rate (f) are obtained by modulating an optical signal by means of a Mach-Zehnder modulator. The modulator is driven by means of a driving signal including, in addition to a sinusoidal component at a frequency (f/2) half the repetition rate (f) of the pulses, at least one odd harmonic of the sinusoidal component. Very short optical pulses can thus be generated without giving rise to undesired side effects such as ringing in pulse tails.

Abstract: In accordance with the invention, a train of RZ or CSRZ pulses is produced by passing phase modulated laser light through a delay interferometer. The parameters of the phase modulation and the delay interferometer are calculated from the desired pulse train characteristics (e.g. repetition rate, RZ or CSRZ, duty cycle). A directly modulated CW laser, or a CW laser followed by a phase modulator, produces the constant amplitude, phase modulated light. The phase modulated signal is split into two paths. One signal path is delayed with respect to the other by the calculated delay. The signals are recombined in an optical coupler to produce an RZ pulse train and/or a CSRZ pulse train.

Abstract: A method of generating a pulse width modulated (PWM) signal receives digital demand data comprising at least one more significant bit and at least one less significant bit. The PWM signal comprises a sequence of one or more frames, each frame comprising a plurality of PWM pulses whose duty cycle is substantially governed by the at least one more significant bit. At least one of its PWM pulses is selected to have its duty cycle modified in response to the at least one less significant bit. Each of the at least one less significant bits uniquely mapping onto the at least one selected PWM pulse of the frame. An apparatus operable according to this method includes an optical attenuator whose optical attenuation is dependent upon its temperature and in which the temperature and, hence, the attenuation is controlled using the above PWM signal.

Abstract: There is provided a two-stage optical regenerator for regenerating a data signal comprising a series of optical pulses. Each stage of the optical regenerator comprises a modulator for modulating a reference signal with an input signal, and an interferometer for causing the modulated reference signal to interfere with another version of the modulated reference signal delayed by less than one bit period of the data signal to regenerate the input signal. The input signal of the modulator of the first stage of the regenerator comprises the data signal, and the input signal of the modulator of the second stage of the regenerator comprises the output from the first stage of the regenerator.

Abstract: There is provided a pulse shaping apparatus for shaping an input optical pulse (500) into an output optical pulse having substantially constant optical power (100, in FIG. 1). The apparatus includes a modulator, which acts upon the input optical pulse (500) under the control of a control signal, and a sampling means, which takes a sample of the incoming optical pulse for further processing. In a feedback configuration, the modulator acts on the incoming pulse under the control of an error signal, the incoming pulse is then sampled, the sample processed and the error signal generated from the processed sample. In a feed-forward configuration, the incoming pulse is sampled first, the sample processed and the modulator acts on the incoming pulse under the control of an error signal resulting from the processing steps.