A method for mitigating modal noise includes applying a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment. A modal-noise mitigator for a multimode optical fiber includes an actuator configured to apply a time-varying mechanical force to a fiber segment of the multimode optical fiber in at least a first direction orthogonal to a fiber axis of the multimode optical fiber within the fiber segment.

A method is provided for detecting primary gas flows (18) in flow chambers (10). The primary gas (18) flowing in a flow chamber (10) is locally seeded with a seed substance and the movement of the seed substance, representative of the flow of the primary gas (18), is detected by imaging by an image detector (28) and an imaging optics (30) arranged in front of said image detector (28). A gas mixture (34) that moves along with the primary gas (18) without relative motion and that has a refractive index distinguishable from that of the primary gas (18) is used as the seed substance, and imaging detection is carried out by a background schlieren measurement method.

A method is provided for detecting primary gas flows (18) in flow chambers (10). The primary gas (18) flowing in a flow chamber (10) is locally seeded with a seed substance and the movement of the seed substance, representative of the flow of the primary gas (18), is detected by imaging by an image detector (28) and an imaging optics (30) arranged in front of said image detector (28). A gas mixture (34) that moves along with the primary gas (18) without relative motion and that has a refractive index distinguishable from that of the primary gas (18) is used as the seed substance, and imaging detection is carried out by a background schlieren measurement method.

According to one embodiment, a light source includes a plurality of light-emitting elements each including one or more surface-emitting lasers; and a plurality of detecting elements located on a same substrate as the light-emitting elements. The detecting elements individually detect quantities of output light of the light-emitting elements.

According to one embodiment, a light source includes a plurality of light-emitting elements each including one or more surface-emitting lasers; and a plurality of detecting elements located on a same substrate as the light-emitting elements. The detecting elements individually detect quantities of output light of the light-emitting elements.

A system for simultaneously detecting audio-characteristics within a body over multiple body surface locations comprising a coherent light source directing at least one coherent light beam toward the body surface locations, an imager acquiring a plurality of defocused images, each is of reflections of the coherent light beam from the body surface locations. Each image includes at least one speckle pattern, each corresponding to a respective coherent light beam and further associated with a time-tag. A processor, coupled with the imager, determines in-image displacements over time of each of a plurality of regional speckle patterns according to said acquired images. Each one of the regional speckle patterns is at least a portion of a respective speckle pattern. Each regional speckle pattern is associated with a respective different body surface location. The processor determines the audio-characteristics according to the in-image displacements over time of the regional speckle patterns.

A system for simultaneously detecting audio-characteristics within a body over multiple body surface locations comprising a coherent light source directing at least one coherent light beam toward the body surface locations, an imager acquiring a plurality of defocused images, each is of reflections of the coherent light beam from the body surface locations. Each image includes at least one speckle pattern, each corresponding to a respective coherent light beam and further associated with a time-tag. A processor, coupled with the imager, determines in-image displacements over time of each of a plurality of regional speckle patterns according to said acquired images. Each one of the regional speckle patterns is at least a portion of a respective speckle pattern. Each regional speckle pattern is associated with a respective different body surface location. The processor determines the audio-characteristics according to the in-image displacements over time of the regional speckle patterns.

An extended optical pulse stretcher is provided that combines confocal pulse stretchers in combination to produce, for example, 4 reflections, 4 reflections, 12 reflections, and 12 reflections per optical circuit configuration. The inclusion of the combination of different mirror separations and delay path lengths can result in very long pulse stretching, long optical delays, and minimal efficiency losses. Also, in the extended optical pulse stretcher, at least a beam splitter can be positioned relative to the center of curvature of the mirrors to “flatten” each of the circuits to enable the beam to propagate in the same plane (e.g., parallel to the floor). Also, the curvatures and sizes of the individual mirrors can be designed to position the beam splitter closer to one of the banks of mirrors to allow the optical pulse stretchers to properly fit in an allocated location in a laser system.

Systems and methods are provided for imaging and characterizing objects including the eye using non-uniform or speckle illumination patterns. According to the present technology, a method for characterizing at least a portion of an object may include generating, using at least one light source, one or multiple non-uniform illumination patterns on an object. The method may also include detecting, using a detector, backscattered light from the object in response to the generating. The method may further include extracting, using the detector, data representative of the backscattered light. The method may also include processing, using a processing unit, the data representative of the backscattered light to create one or more images of at least a portion of the object.

An illumination system and a projection apparatus are provided. The illumination system includes a coherent light source, an optical module, and a first light-diffusing device. The coherent light source emits a coherent light beam. The optical module and the first light-diffusing device are located on a transmission path of the coherent light beam. The optical module has an optical surface and a light-diffusing surface, and the coherent light beam focuses on a first position through the optical surface of the optical module. The first light-diffusing device is located at the first position or in vicinity of the first position. The coherent light beam passes through the first light-diffusing device so that a diffusion angle of the coherent light beam is sequentially changed. A display frame exhibiting a uniform luminance is thereby provided by the illumination system and the projection apparatus of the invention.