Abstract: A system for probing a DUT is disclosed, the system having a pulsed laser source, a CW laser source, beam optics designed to point a reference beam and a probing beam at the same location on the DUT, optical detectors for detecting the reflected reference and probing beams, and a collection electronics. The beam optics is a common-path polarization differential probing (PDP) optics. The common-path PDP optics divides the incident laser beam into two beams of orthogonal polarization—one beam simulating a reference beam while the other simulating a probing beam. Both reference and probing beams are pointed to the same location on the DUT. Due to the intrinsic asymmetry of a CMOS transistor, the interaction of the reference and probing beams with the DUT result in different phase modulation in each beam. This difference can be investigated to study the response of the DUT to the stimulus signal.

Abstract: A bandwidth meter method and apparatus for measuring the bandwidth of a spectrum of light emitted from a laser input to the bandwidth meter is disclosed, which may comprise an optical bandwidth monitor providing a first output representative of a first parameter which is indicative of the bandwidth of the light emitted from the laser and a second output representative of a second parameter which is indicative of the bandwidth of the light emitted from the laser; and, an actual bandwidth calculation apparatus utilizing the first output and the second output as part of a multivariable equation employing predetermined calibration variables specific to the optical bandwidth monitor, to calculate an actual bandwidth parameter.

Abstract: An apparatus and method for laser probing of a DUT at very high temporal resolution is disclosed. The system includes a CW laser source, a beam optics designed to point two orthogonally polarized beams at the same location on the DUT, optical detectors for detecting the reflected beams, collection electronics, and an oscilloscope. The beam optics defines a common-path polarization differential probing (PDP) optics. The common-path PDP optics divides the laser beam into two beams of orthogonal polarization. Due to the intrinsic asymmetry of a CMOS transistor, the interaction of the beams with the DUT result in different phase modulation in each beam. This difference can be investigated to study the response of the DUT to the stimulus signal.

Abstract: A method and an apparatus for measuring optical heterodyne interference in which a reference light and a measurement light differing in frequency is generated. The measurement light is S- or P-polarization light which is irradiated on a target through a polarization light beam splitter, and the reference light is P or S-polarization light which is reflected by a mirror. Interference of the measurement light from the target and the reference light reflected from the mirror is obtained by a light receiving element so as to measure a surface condition or detecting a surface detect on the target. A polarizing plate which is arranged before the light receiving element has an axis rotated so that a signal from the light receiving element becomes a minimum when the reference light is selectively shut off by a light shut off mechanism arranged before the polarization light beam splitter.

Abstract: Interferometric scanning method(s) and apparatus for measuring test optics having aspherical surfaces including those with large departures from spherical. A reference wavefront is generated from a known origin along a scanning axis. A test optic is aligned on the scanning axis and selectively moved along it relative to the known origin so that the reference wavefront intersects the test optic at the apex of the aspherical surface and at one or more radial positions where the reference wavefront and the aspheric surface intersect at points of common tangency (“zones”) to generate interferograms containing phase information about the differences in optical path length between the center of the test optic and the one or more radial positions. The interferograms are imaged onto a detector to provide an electronic signal carrying the phase information.

Abstract: An inspection system is provided to examine internal structures of a target material. This inspection system combines an ultrasonic inspection system and a thermographic inspection system. The thermographic inspection system is attached to ultrasonic inspection and modified to enable thermographic inspection of target materials at distances compatible with laser ultrasonic inspection. Quantitative information is obtained using depth infrared (IR) imaging on the target material. The IR imaging and laser-ultrasound results are combined and projected on a 3D projection of complex shape composites. The thermographic results complement the laser-ultrasound results and yield information about the target material's internal structure that is more complete and more reliable, especially when the target materials are thin composite parts.

Abstract: There are several different applications where it is desirable to increase the amount of material that can be introduced to the surface of a microresonator that has whispering gallery modes. The use of a porous surface on the microresonator permits greater amounts of the material to be captured on or near the surface of the microresonator, resulting in an increased optical interaction between the material and the light propagating in the whispering gallery mode(s) of the microresonator.

Abstract: A method for measuring a layer of a device is provided. In an embodiment, a set of baseline reflectance profiles may be generated from a corresponding set of baseline devices. Each of the baseline devices may include a layer with a known thickness. A reflectance profile may also be generated from the device, which may include a layer with an unknown thickness. The reflectance profile generated from the device may then be compared to the set of reflectance profiles generated from the set of the baseline devices to determine the thickness of the layer of the device.

Abstract: The invention relates to a device for measuring a Doppler frequency shift, including an optical signal channel delivering a signal light beam illuminating a reference medium; and a reference channel delivering a reference light beam for detecting the Doppler frequency shift. The frequency shift is determined from the difference in frequency between the light signal illuminating the reference medium and the light beam returned by the reference medium. The device includes at least two light radiation sources, preferably lasers, with one light radiating source generating the light beam for the signal channel and the other source generating the light beam for the reference channel.

Abstract: A fiber-optic bundle based optical coherence tomography (OCT) probe method is demonstrated in a multimode optical fiber bundle based OCT system. The system can achieve a lateral resolution of 12 ?m and an axial resolution of 10 ?m using a super-luminescent diode source. This imaging approach eliminates any moving parts in the probe and has a primary advantage for use in extremely compact and safe OCT endoscopes to image internal organs and great potential to be combined with confocal endoscopic microscopy.

Abstract: Speckle, a factor reducing image quality in optical coherence tomography (“OCT”), can limit the ability to identify cellular structures that are important for the diagnosis of a variety of diseases. Exemplary embodiments of the present invention can facilitate an implementation of an angular compounding, angular compounding by path length encoding (“ACPE”) for reducing speckle in OCT images. By averaging images obtained at different incident angles, with each image encoded by path length, ACPE maintains high-speed image acquisition and implements minimal modifications to OCT probe optics. ACPE images obtained from tissue phantoms and human skin in vivo demonstrate a qualitative improvement over traditional OCT and an increased signal-to-noise ratio (“SNR”). Accordingly, exemplary embodiments of an apparatus probe catheter and method can be provided for irradiating a sample. In particular, an interferometer may forward forwarding an electromagnetic radiation.

Abstract: Methods and systems are disclosed for analyzing a scanning interferometry signal. Steps include: providing a scanning interferometry signal produced by a scanning interferometer for a first location of a test object (e.g., a sample having a thin film); providing a model function of the scanning interferometry signal produced by the scanning interferometer, wherein the model function is parameterized by one or more parameter values; fitting the model function to the scanning interferometry signal for each of a series of shifts in scan position between the model function and the scanning interferometry signal by varying the parameter values; and determining information about the test object (e.g., a surface height or height profile, and/or a thickness or thickness profile for a thin film in the test object) at the first location based on the fitting.

Abstract: A measuring apparatus provides data relating to the shape of an input radiation wavefront, the wavefront shape being describable at a pre-determined location in an optical system. The apparatus includes an aberration device which provides an aberration to the input radiation wavefront, the shape of which is defined by a filter function that is complex valued and has non-mixed symmetry, and a detector having a radiation sensitive surface capable of detecting the intensity of incident radiation on the surface, the detector being coupled to an output device that provides a measure of the intensity of the incident radiation. The aberration device is configured to act on an input wavefront shape to produce first and second output radiation signals that are detected by the detector and in combination cause the output device to provide data indicating an extent to which the wavefront shape is non-planar.

Abstract: The invention relates to an interferometric method for measuring a height of a first region on a first surface, the first surface having first areas having first optical properties and second areas having second optical properties, the method comprising the steps of generating of first and second coherent light beams, reflecting at least the first coherent light beam from the first region into a first return beam and reflecting the second coherent light beam from a second region into a second return beam, measuring at least a first reflectivity of the first region, determining a topography-dependent phase shift of the first and second return beams for the height measurement based on the first reflectivity.

Abstract: The invention relates to an interferometric method for measuring a height of a first region on a first surface, the first surface having first areas having first optical properties and second areas having second optical properties, the method comprising the steps of generating of first and second coherent light beams, reflecting at least the first coherent light beam from the first region into a first return beam and reflecting the second coherent light beam from a second region into a second return beam, measuring at least a first reflectivity of the first region, determining a topography-dependent phase shift of the first and second return beams for the height measurement based on the first reflectivity.

Abstract: The present invention is directed to a self referencing heterodyne reflectometer system and method for obtaining highly accurate phase shift information from heterodyned optical signals, without the availability of a reference wafer for calibrations. The self referencing heterodyne reflectometer rapidly alternates between a heterodyne reflectometry (HR) mode, in which an HR beam comprised of s- and p-polarized beam components at split angular frequencies of ? and ?+?? is employed, and a self referencing (SR) mode, in which an SR beam comprised of p-polarized beam components at split angular frequencies of ? and ?+?? is employed. When the two measurements are made in rapid succession, temperature induced noise in the detector is be assumed to be the same as for both measurements. A measured phase shift ?Ref/film is generated from the HR beam and a reference phase shift ?Ref/Sub is generated from the SR beam.

Abstract: A fiber optic interferometric position sensor and measurement method thereof suitable for determining the moving direction of a measurement object in an environment of high electric or magnetic field strengths are disclosed. The fiber optic interferometric position sensor comprises at least one light source, a plurality of fiber optic couplers, a plurality of sensing fibers and a plurality of photodetectors. The fiber optic couplers are connected to the at least one light source, the photodetectors, and the sensing fibers, respectively.

Abstract: An optical scanner for use in conjunction with an infrared spectrometer is disclosed. The optical scanner translates a beam of radiation to a stationary spot on a traveling sheet of material so that ample integration time within the spectrometer is achieved. The beam path impinges on the traveling web and the radiation is reflected off the traveling web back through the optical scanner and recombined at an interferometer. The beam of radiation is kept stationary with respect to both the traveling sheet and the carriage which houses the spectrometer.

Abstract: The aim of the invention is to provide a method for determining the frequency response of an electrooptical component, particularly, for example, of a light-generating or light-modulating component, which is easy to carry out. To this end, the invention provides a method during which optical pulses with a pulse frequency (fp) are generated. The electrooptical component (60) is controlled by an electrical measuring signal (Smess) with a measuring frequency (fmess) in such a manner that an optical output signal (Saus) is formed that is modulated with the measuring frequency (fmess). The measuring frequency (fmess) is equal to an integral multiple of the pulse frequency (fp) plus a predetermined frequency offset ($g(D)f). The pulses and the output signal (Saus) are mixed, and a mixed product (M) is detected whose modulation frequency corresponds to the predetermined frequency offset ($g(D)f).

Abstract: The present invention relates to an optical interferometric apparatus and method for measuring acceleration, pressure, and pressure of fluids during flow using micro-opto-electro-mechanical-systems (MOEMS). The high-sensitivity and high-resolution apparatus includes a movable mass, a stationary mass, a light source, and a photo detector. The light source emits a beam which is converted into two beam portions after impinging onto the movable and stationary masses. Interference between the beam portions are used to measure acceleration or pressure. The MOEMS structure may be integrated with a photo detector or planar waveguide. Differential amplification can be realized by employing two similar detecting structures.