Abstract: In an imaging system providing an image of a target of interest, a method of reducing interference from a laser beam includes the steps of: (a) receiving optical energy from the target of interest and the laser beam; (b) forming an interferogram of spectral energy, at each spatial position of an image, based on the optical energy received in step (a); (c) detecting the interferogram of spectral energy, at each of the spatial positions, to provide a corresponding spectral band of intensity values; (d) selecting an intensity level in the spectral band, detected in step (c), that is greater than a predetermined value, and reducing the selected intensity level; and (e) forming an image of the target of interest, after reducing the selected intensity level of step (d).

Abstract: Systems and methods are described for rapid acquisition of fused off-axis illumination direct-to-digital holography. A method of recording a plurality of off-axis object illuminated spatially heterodyne holograms, each of the off-axis object illuminated spatially heterodyne holograms including spatially heterodyne fringes for Fourier analysis, includes digitally recording, with a first illumination source of an interferometer, a first off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; and digitally recording, with a second illumination source of the interferometer, a second off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis.

Abstract: Methods and systems for using dynamic light scattering, for investigating local rheological responses of complex fluids over a frequency range larger than that provided by standard instrumentation. A low-coherence radiation source is used with fiber optics to allow measurements of small volume spacing of up to approximately 1/10 of a picoliter. The methods and systems are based on dynamic light scattering, for investigating the local rheological response of a complex fluid over a frequency range larger than that provided by standard mechanical instrumentation. The low-coherence radiation used in a fiber optics configuration allows the measurements to be confined to a small volume around a tenth of a picoliter. The ability of the method to accurately measure both loss and storage moduli has been tested using both simple Newtonian liquids and viscoelastic, complex fluids. Monitoring liquid-gel transitions in polymer solutions has also been demonstrated.

Abstract: A dual electrooptic interferometer and method for operation thereof. In a preferred embodiment, the interferometer includes first and second electro-optically active optical waveguides; a first electrode substantially parallel to the first waveguide in a traveling wave modulator configuration; a second electrode substantially parallel to the second waveguide in a traveling wave modulator configuration; and a photo detector array optically coupled to the outputs of the waveguides.

Abstract: A laser-based measuring apparatus divides a light beam from a laser light source into at least two light beams, passes the light beams through different optical paths from each other, recombines the light beams, has the light beams interfere with each other to generate interfered light, opto-electrically transduces the interfered light to an optical frequency, and measures the amount of travel of an object which changes an optical path length of a portion of an optical path based on the optical frequency. The measuring apparatus has a portion for generating at least two measuring light beams from the laser light source, two reflection planes included in an object moving on a measuring axis, arranged back-to-back to each other on the measuring axis, and an opposing incident optical system for directing the measuring light beams into the reflection planes, respectively, such that the measuring light beams oppose to each other on the measuring axis.

Abstract: A method and apparatus for measuring bandwidth of light emitted from a laser which may comprise: first and second wavelength sensitive optical bandwidth detectors providing, respectively, an output representative of a first parameter indicative of the bandwidth of the emitted light as measured respectively by the first and second bandwidth detectors, and an actual bandwidth calculation apparatus adapted to utilize these two outputs as part of a multivariable linear equation employing predetermined calibration variables specific to either the first or the second bandwidth detector, to calculate a first actual bandwidth parameter or a second actual bandwidth parameter. The first actual bandwidth parameter may be a spectrum full width at some percent of the maximum (“FWXM”), and the second actual bandwidth parameter may be a portion containing some percentage of the energy (“EX”).

Abstract: Method and system are disclosed for de-embedding optical component characteristics from optical device measurements. In particular, the invention uses frequency domain averaging of the RBS on both sides of an optical component to determine one or more of its optical characteristics. Where the RBS has a slope (e.g., as in the case of a lossy fiber), a frequency domain least square fit can be used to determine the optical component characteristics. In addition, the invention uses a reference DUT to correct for variations in the frequency response of the photoreceiver. A reference interferometer is used in the invention to correct for sweep non-linearity of the TLS. The optical component characteristics are then de-embedded from optical device measurements to provide a more precise analysis of the optical device.

Abstract: An instrument including a scannable mirror employs multimode optical fibers and an optical coupler. Modal dispersion, e.g., from the multimode optical fiber, is reduced by a method employing deconvolution. The scannable mirror may employ a mirror movable in an optical waveguide or an optical fiber wound on an expandable core.

Abstract: In an optical heterodyne surface plasma wave detecting method and apparatus, light that contains correlated P1 and P2 wave components (TM waves) is directed to a total reflective component such that two surface plasma waves are generated at an interface of a metal film and a test object. Light reflected from the total reflective component is detected to obtain an optical heterodyne test signal that is compared with an optical heterodyne reference signal to determine changes in at least one of amplitude and phase of the optical heterodyne signal relative to the optical heterodyne reference signal.

Abstract: Interferometric apparatus and methodology for precisely measuring the shape of rotationally and non-rotationally symmetric optical surfaces comprising an illumination source with two wavelengths, a transmission flat with a reference surface, a basic optical system for producing a wavefront of predetermined shape, a compensation component having an aspheric wavefront shaping surface and an aspheric reference surface. The aspheric shaping surface modifies the predetermined wavefront so that it impinges on the aspheric reference surface with a shape substantially that same as that of aspheric reference surface. For a given aspheric reference surface, the radius or curvature and spacing of the aspheric shaping surface are optimized so that its aspheric departure is no larger than that of the aspheric reference surface. Precise alignment in six degrees of freedom is provided via feedback control.

Abstract: Systems, methods, computer-readable media for determining optical characteristics, such as polarization mode dispersion and/or polarization dependent loss, of device under test (DUTs) are provided. In this regard, one such system includes a response analyzer that receives data corresponding to responses of a DUT to optical signals. The response analyzer computes fast and slow group delays corresponding to at least some of the optical signals, each of the fast and slow group delays being attributable to one of a first and a second principle state of polarization. The response analyzer then assigns each of the fast and slow group delays to a correct one of the first and second principle states of polarization for at least some of the optical signals.

Abstract: Apparatus for optical assessment of a sample includes a radiation source, adapted to generate a beam of coherent radiation, and traveling lens optics, adapted to focus the beam so as to generate first and second spots on a surface of the sample and to scan the spots together over the surface. The distance between the first and second spots is responsive to a pitch of a repetitive pattern of the sample. Collection optics are positioned to collect the radiation scattered from the first and second spots and to focus the collected radiation so as to generate an interference pattern. A detector detects a change in the interference pattern.

Abstract: An athermal interferometric wavelocker is disclosed having a beam splitter combiner and a first arm of a first material having a first refractive index, a first length, and a first coefficient of expansion; and, a second arm of a second material having a second refractive index, a second length, and a second coefficient of expansion. The refractive indices, lengths and coefficients of expansion of the first arm and the second arm are selected to provide a substantially athermal structure operating at ambient temperatures. The first arm and second arm have inner end faces that meet adjacent faces of the beam splitter and combiner. The first and second arms are of a different optical path length such that light launched into the beam splitter and combiner, interferes upon recombining, and is output from a combiner output port to provide a wavelocker signal having a detectable characteristic which varies with wavelength.

Abstract: A monolithically integrated semiconductor laser rotation sensor/gyroscope that includes at least two isolated, nonsynchronized semiconductor lasers; at least one being unidirectional and at least a further one being either a straight-line laser or a second unidirectional ring laser configured to propagate lasing light waves in the direction opposite to the first unidirectional ring laser; semiconductor directional waveguide couplers; a semiconductor Y-junction mixing region; and a semiconductor photodetector. Evanescently outcoupled signals are routed to a photodetector for detection of the Sagnac shifted frequencies to discern a beat frequency resulting from rotation of the chip structure. The straight-line semiconductor laser serves as frequency reference insensitive to rotation. Directing, filtering, and radiating unwanted reflections or backscattered light to highly absorbing regions is carried out with waveguide coupler designs and nonreciprocal couplers and filters.

Abstract: A method for determining relative movement between an optical navigation device and a navigation terrain includes generating two overlapping coherent optical beams, and generating a pattern of interference fringes between the two overlapping optical beams. The method further includes illuminating a surface portion of the navigation terrain with the pattern of interference fringes, imaging a fringe-illuminated surface portion, and generating a pattern of signals in response to the imaged fringe-illuminated surface portion.

Abstract: The present invention is directed at a coherence test reticle or lithographic plate, and a method for testing the coherence of a laser beam using the test reticle. The quality or coherence of the laser beam is measured by illuminating the test reticle and the recording and/or analyzing the optical patterns generated by the illumination. The technique was designed for, but not limited to, the characterization of laser-based systems via the detection of optical radiation modulated by transmissive, reflective and diffractive patterns printed on a reticle or lithographic plate designed specifically for this purpose. The novelty and advantages over the prior art are insensitivity to vibration, alignment, and multi-path differences of classical interferometric coherence measurement techniques. Spatial coherence and longitudinal or temporal coherence may be measured independently. Vertical and horizontal coherence may be measured independently. The technique is focus error insensitive.

Abstract: A digitally aberration corrected miniaturized holographic Fourier transform spectrometer (HFTS) made from simple optical components and with no moving parts is provided. The disclosed digitally aberration corrected HFTS is comprised of a two beam interferometer, which provides two interfering beams; a 2D array detector to detect the interference pattern created by the beams; a computer for correcting effects of aberrations in the pattern and calculating the spectrum from thus corrected interferogram.

Abstract: An interferometry method including: i) forming an optical interference image by combining different portions of an optical wave front reflected from multiple surfaces; ii) recording an interference signal at different locations of the optical interference image in response to varying a property of the optical wave front that causes pairs of the multiple surfaces that have different optical path separations to contribute differently to the interference signal; iii) transforming the interference signal for at least one of the locations to produce a spectrum having a peak at a spectral coordinate corresponding to each pair of the multiple surfaces; and iv) identifying the spectral coordinate of the peak corresponding to a selected pair of the multiple surfaces.

Abstract: A point source module is provided, comprising: a Shack cube comprising a beam splitter cube with an attached spherical reference surface defining a reference arm; a test arm that is associated with transmission of optical radiation from a source to a sample; a point source of optical radiation whose emissions traverse both the reference arm and the test arm; and a detector associated with a surface of the beam splitter cube and receiving optical radiation from both the reference arm and the test arm and comprising a detector arm, an objective lens associated with the test arm, or both. Further, a method of aligning the point source module is provided, along with a method of using the point source microscope is provided. The apparatus and methods provide a compact, robust device and technique for measuring or locating optical or mechanical datum of parts that are being manufactured or assembled.

Abstract: A position detecting system includes a light source device for providing coherent light, an incoherence-transforming device for transforming the coherent light from the light source device, into incoherent light, an optical system for dividing the incoherent light from the incoherence-transforming device into divided light, wherein one of the divided light beams produces an intermediate image, and light from the intermediate image is directed to illuminate a target upon a surface of an object while another of divided light beams is directed to be reflected by a surface which is optically conjugate with the intermediate image, and wherein light from the target and light reflected by the conjugate surface are re-combined, an image pickup device for producing an imagewise signal corresponding to the target on the basis of the light re-combined by the optical system, wherein positional information related to a position of the target with respect to a direction along the surface of the object can be produced on th