Patent application number | Description | Published |
20080308716 | Automatic photodiode biasing circuit - A biasing circuit for a photodiode. The novel biasing circuit includes a first system for setting a reference gain threshold, a second system for setting an operating gain threshold, and a third system for adjusting a bias of the photodiode until a ratio of the operating gain threshold to the reference gain threshold is equal to a predetermined factor Z. In an illustrative embodiment, the reference gain threshold corresponds to a given probability of an output of the photodiode crossing the reference gain threshold when the photodiode is operating at a reference gain bias, and the operating gain threshold corresponds to a given probability of the photodiode output crossing the operating gain threshold when the photodiode is operating at an operating gain bias. The predetermined factor Z is a ratio of noise at a desired operating gain of the photodiode to noise at the reference gain of the photodiode. | 12-18-2008 |
20100232007 | Linear adaptive optics system in low power beam path and method - A system and method for providing a wavefront corrected high-energy beam of electromagnetic energy. In the illustrative embodiment, the system includes a source of a first beam of electromagnetic energy; an amplifier for amplifying said beam to provide a second beam; a sensor for sensing aberration in said second beam and providing an error signal in response thereto; a processor for processing said error signal and providing a correction signal in response thereto; and a spatial light modulator responsive to said correction signal for adjusting said beam to facilitate a correction of said aberration thereof. In more specific embodiments, the source is a laser and the sensor is a laser wavefront sensor. A mirror is disposed between said modulator and said sensor for sampling said beam. The mirror has an optical thin-film dielectric coating on at least one optical surface thereof. The coating is effective to sample said beam and transmit a low power sample thereof to said means for sensing aberration. The processor is an adaptive optics processor. The spatial light modulator may be a micro electro-mechanical system deformable mirror or an optical phased array. In the illustrative embodiment, the source is a master oscillator and the amplifier is a power amplifier beamline. An outcoupler is disposed between the oscillator and the amplifier. | 09-16-2010 |
20110228386 | LOW ORDER ADAPTIVE OPTICS BY TRANSLATING SECONDARY MIRROR OF OFF-APERTURE TELESCOPE - In one or more embodiments, a beam control apparatus and method for correcting aberrations include an off-aperture telescope configured to receive a beam of electromagnetic energy, wherein the telescope includes a first optical element and a second optical element. The second optical element is configured to be translated in three orthogonal axes, and a wavefront error sensor is configured to detect aberrations in the beam and to provide a wavefront error signal in response thereto. A processor is configured to provide a correction signal in response to the wavefront error signal, and an actuator is coupled to the second optical element and configured, in response to the wavefront error signal, to selectively translate the second optical element in one or more of three substantially orthogonal directions corresponding to the three orthogonal axes. | 09-22-2011 |
20110235871 | TEXTURED PATTERN SENSING USING PARTIAL-COHERENCE SPECKLE INTERFEROMETRY - A system for imaging a textured surface includes a light source that is configured to project an electromagnetic radiation beam onto the textured surface, wherein the projected beam generates first radiation reflected from a first portion of the textured surface to form a speckle pattern, and second radiation reflected from a second portion of the textured surface which is substantially uniform in intensity. The reflected first and second reflected radiation is received by an optical detector, and may be processed to generate an image of the textured surface from the first and second reflected radiation. Methods for textured surface sensing are also disclosed. | 09-29-2011 |
20110242285 | IMAGING SYSTEM AND METHOD USING PARTIAL-COHERENCE SPECKLE INTERFERENCE TOMOGRAPHY - A system for generating an image of contoured surface includes a light source that is configured to project an electromagnetic radiation beam onto the contoured surface, wherein the projected beam generates first radiation reflected from a first portion of the contoured surface to form a speckle pattern, and second radiation reflected from a second portion of the contoured surface which is substantially uniform in intensity. The reflected first and second reflected radiation is received by an optical detector, and may be processed. The processing is configured to (1) generate a plurality of images from the first and second reflected radiation, with each image being generated using different coherence length electromagnetic radiation from the light source, and (2) generate a 3-D image of the contoured surface from the plurality of images. Methods for generating a 3-D image of a contoured surface are also disclosed. | 10-06-2011 |
20110261191 | TEXTURED PATTERN SENSING AND DETECTION, AND USING A CHARGE-SCAVENGING PHOTODIODE ARRAY FOR THE SAME - A system for imaging a textured surface comprising includes a photoreceptor array having: at least a first photoreceptor and a second photoreceptor, each configured to receive electromagnetic radiation reflected from the textured surface and to generate a signal corresponding thereto; wherein the photoreceptor array is configured to detect an image of the textured surface based on the relative difference between the time of arrival of the signals from the first and second photoreceptors. Methods for imaging a textured surface and fabricating a photoreceptor array structure for imaging a textured surface are also provided. | 10-27-2011 |
20110281387 | METHOD OF MANUFACTURING A LASER GAIN MEDIUM HAVING A SPATIALLY VARIABLE GAIN PROFILE - Method of manufacturing a laser medium with a material having a surface and a dopant in the material distributed whereby the material has a spatially variant optical flux density profile uses tailored non-uniform gain profiles within a Yb:YAG laser component (rod, slab, disc, etc.) achieved by a spatial material modification in the spatially masked pre-forms. High temperature-assisted reduction leads to the coordinate-dependent gain profiles, which are controlled by the topology of the deposited solid masks. The gain profiles are obtained by reducing the charge state of the laser-active trivalent Yb | 11-17-2011 |
20120057238 | LOW-ABERRATION OPTICAL WINDOW - An optical window may be configured to minimize optical aberrations. The optical window may include a laminous optical window assembly. The laminous optical window assembly may have four or more alternating layers of positive refraction material layers and negative refraction material layers. The four or more alternating layers may be configured to minimize refraction of electromagnetic rays propagating therethrough such that a given incident electromagnetic ray is substantially collinear with a corresponding transmitted electromagnetic ray. | 03-08-2012 |
20130044779 | METHOD FOR TAILORING THE DOPANT PROFILE IN A LASER CRYSTAL USING ZONE PROCESSING - A lasing medium having a tailored dopant concentration and a method of fabrication thereof is disclosed. The lasing medium has a single crystal having a continuous body having a selected length, wherein the crystal comprises dopant distributed along the length of the body to define a dopant concentration profile. In one embodiment, the dopant concentration profile results in a uniform heating profile. A method of fabricating a laser crystal having a tailored dopant concentration profile includes arranging a plurality of polycrystalline segments together to form an ingot, the polycrystalline segments each having dopant distributed, providing a crystal seed at a first end of the ingot, and moving a heating element along the ingot starting from the first end to a second end of the ingot, the moving heating element creating a moving molten region within the ingot while passing therealong. | 02-21-2013 |
20140247372 | FOVEATED IMAGING SYSTEM AND METHOD - A time-varying image is synthesized having at least one time-varying region of interest therewithin. The image is spatially modulated with an array of modulating pixels to form a modulated image. The array of modulating pixels has a modulator resolution. The modulated image is sensed with an array of sensor pixels. The array of sensor pixels has a sensor resolution. The modulator resolution is finer than the sensor resolution. Each sensor pixel corresponds to a plurality of modulating pixels. Said sensor pixel and said plurality of modulating pixels subtend the same region in the image. Outside the region of interest, the modulated image is synthesized at the sensor resolution and at a sensor video frame rate. Inside the region of interest, the modulated image is synthesized at the modulator resolution and at an effective synthesized video frame rate that is less than sensor video frame rate. | 09-04-2014 |
20140263982 | SENSOR INCLUDING DIELECTRIC METAMATERIAL MICROARRAY - The present disclosure is directed to electromagnetic radiation sensors including micro-lenses and to methods of constructing and utilizing such electromagnetic radiation sensors. In one embodiment there is provided an electromagnetic radiation sensor comprising a dielectric substrate including a front surface and a rear surface, an electromagnetic radiation detector element disposed on the rear surface of the substrate, and a lens comprising a three dimensional polaritonic metamaterial structure including a pattern of features formed in the front surface of the substrate, the lens configured to focus electromagnetic radiation incident on the front surface of the substrate onto the electromagnetic radiation detector element. | 09-18-2014 |