Abstract: An interferometer of the present invention includes: a splitting element which splits an incident light beam into a first split beam and a second split beam; and a first phase compensator which is positioned in an optical path of the first split beam, and which compensates a phase difference occurring between the first split beam and the second split beam upon splitting of the incident light beam by said splitting element.

Abstract: An ophthalmic surgical microscope (100) has a microscope main objective (101) and a viewing beam path (105) which passes through the microscope main objective (101) for visualizing an object region. The ophthalmic surgical microscope (100) includes an OCT-system (140) for recording images of the object region (108). The OCT-system (140) includes an OCT-scanning beam (142) which is guided via a scan mirror arrangement (146) to the object region (108). An optic element (147) is provided between the scan mirror arrangement (146) and the microscope main objective (101). This optic element (147) bundles the OCT-scanning radiation exiting from the scan mirror arrangement (146) and transfers the same into a beam path which passes through the microscope main objective (101). Alternatively or in addition, the ophthalmic surgical microscope (100) includes an opthalmoscopic magnifier lens (132) which can be pivoted into and out of the viewing beam path (105) and the OCT-scanning beam (142).

Abstract: A high-speed absorption spectrographic system employs a slit-less spectroscope to obtain high-resolution, high-speed spectrographic data of combustion gases in an internal combustion engine allowing precise measurement of gas parameters including temperature and species concentration.

Abstract: A method of ultrasonic testing comprising conditioning a radiation wave from a laser source by efficiently converting the radiation wave's wavelength to a mid-IR wavelength for enhanced ultrasonic testing of a composite. The method includes passing the radiation wave through a first optical frequency converter where the radiation wave is converted into a signal wave and an idler wave, where the idler wave is at a mid-IR wavelength. The method further includes directing the signal and idler waves to a second optical frequency converter where the signal wave wavelength is converted to a mid-IR wavelength which combines with the idler wave to form a generation wave. The generation wave is directed at a composite surface to be tested.

Abstract: Interference in a rotation rate detector signal of an interferometric fiber-optic gyroscope from a bias phase modulator signal may be reduced or substantially avoided by transmitting one or more off-frequency signals having a frequency other than the eigenfrequency of the gyroscope towards a bias phase modulator, generating the bias phase modulator signal having a frequency substantially equal to the eigenfrequency of the gyroscope, and driving the bias phase modulator with the bias phase modulator signal.

Abstract: An inhomogeneous optical cavity is tuned by changing its shape, such as by changing reflection surface positions to change tilt angle, thickness, or both. Deformable components such as elastomer spacers can be connected so that, when deformed, they change relative positions of structures with light-reflective components such as mirrors, changing cavity shape. Electrodes can cause deformation, such as electrostatically, electromagnetically, or piezoelectrically, and can also be used to measure thicknesses of the cavity. The cavity can be tuned, for example, across a continuous spectrum, to a specific wavelength band, to a shape that increases or decreases the number of modes it has, to a series of transmission ranges each suitable for a respective light source, with a modulation that allows lock-in with photosensing for greater sensitivity, and so forth.

Abstract: A new optical ultrasonic analysis transducer is described. The device includes a new detection means for the reflected ultrasound signal. The detector may be incorporated into a microchip design. The detector is compatible with a variety of material and design geometries that may be optimized for the particular application. Versions of the device may optionally include both excitation and receiving elements on the same device or these elements may be separate. Example designs are shown with applications to continuous wave ultrasound analysis useful for example in Doppler fluid flow measurements. Other designs are shown with multiple arrays and multiple excitation transducers to allow flexible three-dimensional imaging apparatus to be built. An equivalent circuit analysis of the frequency response and signal sensitivity provides means to customize material selection and other design parameters for particular applications.

Abstract: According to one embodiment of the present invention, a method of determining the depth profile of a surface structure includes: irradiating the surface structure with irradiation light including light components of different wavelengths; and determining the depth profile of the surface structure in dependence on interferometric effects caused by the reflection of the irradiation light at the surface structure.

Abstract: A method of imaging critical dimensions by measuring the zeroeth order of diffracted light. The method involves providing a target, directing light onto the target so as to cause the target to diffract the light. The zeroeth order of the diffracted light is collected and analyzed to determine structural features of the target. The target can be an article of manufacture, such as a semiconductor device, or a separate target that is provided or fabricated on an article of manufacture. One of at least the wavelength and the angle at which the light is directed onto the target can be scanned. The target can fill all or only a portion of the field of view.

Abstract: An explicit relationship is developed between the ratio of average interferometric modulation produced by diamond-like carbon (DLC)-coated magnetic-head surfaces and the thickness of the DLC layer. Accordingly, the thickness of the DLC layer is calculated in various manners from modulation data acquired for the system using object surfaces of known optical parameters.

Abstract: Characterization of an optical system is quickly and easily obtained in a single acquisition step by obtaining image data within a volume of image space. A reticle and image plane are positioned obliquely with respect to each other such that a reticle having a plurality of feature sets thereon, including periodic patterns or gratings, is imaged in a volume of space, including the depth of focus. Metrology tools are used to analyze the detected or recorded image in the volume of space through the depth of focus in a single step or exposure to determine the imaging characteristics of an optical system. Focus, field curvature, astigmatism, spherical, coma, and/or focal plane deviations can be determined. The present invention is particularly applicable to semiconductor manufacturing and photolithographic techniques used therein, and is able to quickly characterize an optical system in a single exposure with dramatically increased data quality and continuous coverage of the full parameter space.

Abstract: A laser based coordinate measuring device measures a position of a remote target. The laser based coordinate measuring device includes a stationary portion, a rotatable portion, and at least a first optical fiber. The stationary portion has at least a first laser radiation source and at least a first optical detector, and the rotatable portion is rotatable with respect to the stationary portion. The first optical fiber system, which optically interconnects the first laser radiation source and the first optical detector with an emission end of the first optical fiber system, has the emission end disposed on the rotatable portion. The emission end emits laser radiation to the remote target and receives laser radiation reflected from the remote target with the emission direction of the laser radiation being controlled according to the rotation of the rotatable portion.

Abstract: A position-measuring device is used for measuring the position of an object relative to a tool, the tool having a tool center point. The position-measuring device includes at least two intersected scales displaceable relative to each other in at least one plane of movement, and an assigned optical scanning unit which generates position signals for at least one measuring direction parallel to the plane of movement. Each scale has a neutral pivot, about which a tilt of the respective scale causes no change of the detected position. The scanning optics ensure that the position of the neutral pivots of the two scales correspond. The positioning of the scales relative to the tool center point ensures that the neutral pivots of the two scales and the tool center point lie in a plane which is parallel to the plane of movement.

Abstract: Optical communications can be performed using spectral interferometry. An incident transmission pulse or beam may be mixed with a locally generated beam or pulse to create an interference pattern that may be analyzed to extract the transmitted data. The incident transmission pulse or beam may also be split and mixed with itself to create an interference pattern.

Abstract: In an optical tomography system, a polarization changing system which converts linearly polarized light too non-linearly polarized light is provided in at least one of a light source unit, an optical path from the light source unit to a light dividing system, the optical path of the measuring light from the light dividing system to an object, the optical path of the reflected light from the object to the combining system and the optical path of the reference light from the light dividing system to the combining system. The polarization changing system is, for instance, a polarization-preserving optical fiber which is disposed so that the direction of polarization of the linearly polarized light and the direction of axis of polarization of the linearly polarized light differ from each other.

Abstract: A Doppler Asymmetric Spatial Heterodyne (DASH) spectrometer includes an input aperture for receiving an input light; a collimating lens for collimating the input light into a collimated light; offset establishing means, including at least one grating, for i) receiving and splitting the collimated light into a first light wavefront in a first optical path and into a second light wavefront in a second optical path, ii) establishing an offset in a light wavefront path distance between the first and second optical path light wavefronts, and iii) diffracting and recombining the first and second optical path light wavefronts into an interference wavefront to form an interference image that includes a plurality of phase points of a heterodyned interferogram measured simultaneously over the path distance offset; and an output optics section comprising a detector for receiving the interference image and outputting an interference image pattern.

Abstract: A measurement method of measuring a wavefront aberration of an optical system to be measured, comprising a first measurement step of measuring wavefronts of the optical system to be measured with respect to linearly polarized light beams along at least three different azimuths, a first calculation step of calculating a wavefront of the optical system to be measured with respect to non-polarized light and a birefringent characteristic of the optical system to be measured, based on the wavefronts of the optical system to be measured, which are measured in the first measurement step, and a second calculation step of calculating a wavefront of the optical system to be measured with respect to arbitrary polarized light, based on the wavefront and the birefringent characteristic of the optical system to be measured, which are calculated in the first calculation step.

Abstract: In a near-field heterodyne spectroscopy system, a near-field generation device receives the output of a pump beam source and is also made to vibrate or move at a frequency f to generate a modulated near-field beam having a near-field component. The outputs of the pump beam source and a probe beam source (optional) as well as the modulated near-field beam are directed to the same point on a sample. At least one of the outputs of the pump beam source and probe beam source is modulated at a frequency ?. Thus, the reflected beam that results from the interaction with the region illuminated by the modulated near-field beam is modulated at frequencies ?+f and ??f. Because the excitation is near-field, the electric field in the sample is evanescent and ensures a shallow probing depth as well as smaller lateral dimensions beyond diffraction limit.

Abstract: The invention relates to a device (10) for determining absorption of a sample, comprising an incoherent radiation source (12) for generating a measuring light beam (20), a resonator that is provided with at least two mirrors (30, 32) into which the measuring light beam can be coupled, a sample volume (38) for receiving an absorbing sample within the resonator (14), and a detector (18) for absorbing the radiation that can be decoupled from the resonator (14). The inventive device (10) includes spectrometric or interferometric means (16), provided between the radiation source (12) and the detector (18), for spectrally splitting the measuring light beam. Means may also be provided for generating a signal that represents the amplitude of the measuring light beam independently of the phase.

Abstract: A method for optical flying height measurement, and a flying height tester.