Abstract: A depolarizer 11 is inserted between an optical branch unit 2 and a polarization filter 3, a depolarizer 12 and a polarization filter 14 are inserted between an optical phase modulator 5 and a quarter-wave plate 16, and a depolarizer 13 and a polarization filter 15 are inserted between the other branch end of the optical branch unit 4 and a quarter-wave plate 17. The optical branch unit 2 and the optical phase modulator 5 are formed by single mode optical fibers, and single mode optical fibers are used to connect between optical elements, thus providing an arrangement which is inexpensive as a whole.

Abstract: A device for measuring wavelength of an electromagnetic signal has first and second waveguides configured such that a portion of an electromagnetic signal transmitted through the first waveguide is separated from the remaining portion of the electromagnetic signal and is communicated to the second waveguide and is subsequently at least partially recombined with the remaining electromagnetic signal in the first waveguide after traveling a distance which is different from a distance traveled by the remaining electromagnetic signal in the first waveguide. A first sensor is configured to measure the power of the electromagnetic signal in the first waveguide after at least a portion of the separated electromagnetic signal in the first waveguide has been recombined with the remaining electromagnetic signal in the first waveguide.

Abstract: A method and apparatus for wavefront analysis including obtaining a plurality of differently phase changed transformed wavefronts corresponding to a wavefront being analyzed which has an amplitude and a phase, obtaining a plurality of intensity maps of the plurality of phase changed transformed wavefronts and employing the plurality of intensity maps to obtain an output indicating the amplitude and phase of the wavefront being analyzed.

Abstract: A device for exposing several rows of mask patterns on a strip-shaped workpiece without the device becoming larger and the rolls having to be replaced is achieved as follows: A strip-shaped workpiece is transported. When a first exposure area of the first row reaches a projection site on a workpiece carrier (3), the strip-shaped workpiece (Wb) is held by vacuum. A mask (M) is positioned relative to the strip-shaped workpiece and the first exposure area is exposed. Then, the strip-shaped workpiece is held by the workpiece suction devices (8, 8′). The movement devices (9) are driven and the strip-shaped workpiece is moved in the direction which orthogonally intersects the transport direction so that a second exposure area of the second row reaches the projection site on the workpiece carrier. The mask is positioned to the strip-shaped workpiece and exposes the second exposure area.

Abstract: An optical sphere of nominal radius is positioned and supported within an assembly so that is can be activated with a predetermined motion with respect to an incoming converging spherical wavefront from an interferometer to calibrate the interferometer by determining the differences between the converging spherical wavefront and the reflected wavefront from portions of the area of the optical sphere as sampled thereover. The nominal optical sphere supported and sampled in this way mimics a “perfect” comparison sphere from which the systematic error of the interferometer wavefront may be determined. The optical sphere is preferably hollow and composed of Zerodur®. Internal magnets in conjunction with external induction coils provide motion control while the optical sphere is mounted on an air bearing for freedom of rotation and safety in transportation.

Abstract: A system and method for in-line inspection of specimens such as semiconductor wafers is provided. The system provides scanning of sections of specimens having predetermined standardized characteristics using a diffraction grating that widens and passes nth order (n>0) wave fronts to the specimen surface and a reflective surface for the transmitted light beam. Light energy is transmitted in a narrow swath across the portion of the surface having the standardized features. The wavefronts are combined using a second diffraction grating and passed to a camera system having a desired aspect ratio.

Abstract: Interferometeric apparatus for analyzing the wavefront and intensity distribution of collimated beams from fiber optic collimators, lasers, and the like. The collimated beams are directed through a plate beamsplitter and combined with a well defined diverging, spherical reference beam preferably generated by a single mode fiber. Reference and test beams are directed through an optical assembly for changing magnification to selectively control lateral resolution at a detector plane. Phase shifting analysis is performed on the resultant interference patterns to analyze the wavefront, and intensity profile is determined as a separate step.

Abstract: Light under measurement whose wavelength is continuously swept is incident on fiber-optic Etalon. The fiber-optic Etalon transmits the light under measurement each time the wavelength of the light under measurement satisfies specific conditions. A PD detects the transmitted light of the fiber-optic Etalon and outputs the intensity of the light under measurement. A counter counts the number of peaks of the output of the PD. A CPU calculates the wavelength of the light under measurement based on the count value of the counter.

Abstract: A delay time measurement apparatus for an optical element includes a pulse light source, wavelength setting unit, optical power divider, optical delay unit, controller, and detector. The pulse light source can vary the wavelength of light to be output, and outputs an optical pulse having a predetermined repetition period. The wavelength setting unit sets the wavelength of light to be output from the pulse light source. The optical power divider divides the optical pulse output from the pulse light source into a first optical pulse and a second optical pulse to be input to an optical element as the object to be measured. The optical delay unit can vary the spatial optical path length along which the first optical pulse divided by the optical power divider travels. The controller changes the spatial optical path length of the optical delay unit.

Abstract: Infrasound signals in the band 0.02 to 4 Hz are sensed in the presence of ambient noise generated chiefly by wind as integrated pressure variations, which induce detectable changes in the optical path length, along optic fibers, typically extending 100 m. to 1000 m. and more, arrayed at arbitrary geometries. Two fibers connected as a Michelson, Mach-Zehnder or equivalent interferometer where (i) one fiber is coupled to atmosphere while (ii) the other is not for being hermetically sealed in a tube, permit common mode rejection of noise from (i) temperature changes and (ii) strain, including ground vibration. Because the optic fiber infrasound sensors are longer than the distance over which wind-induced pressure changes are coherent, the effects of wind noise on the sensing of infrasound is reduced, and signal-to-noise ratio is increased over a wide bandwidth.

Abstract: An optical frequency discriminator includes an interferometer cascaded with an absorption cell that provide a composite signal. A receiver samples a composite signal and maps to the sample positions of the acquired samples, corresponding optical frequencies of an applied optical signal.

Abstract: Rapid scan optical delay techniques are used in parallel implementation of OCT using a detector and signal processing can be carried out using algorithms. Frequency encoded parallel OCT and multi-path, frequency encoded reference delay networks are used. A large number of frequency-correlated depth channels are used to acquire multiple depth scans of a sample. A different frequency shift (Doppler shift) on each different path length, or delay, is used to obtain simultaneous respective signals and, thus, information about the sample, from different depths in the sample. Reference delay line functions are obtained using bulk optics, integrated optics and fiber optics.

Abstract: An analysis method for analyzing height-scanning interferometry data from a test surface, the method including: calculating a coherence profile and a phase profile for the test surface based on the data; calculating an experimental phase gap map based on a difference between the phase profile and the coherence profile; filtering the experimental phase gap map to remove noise; and using the filtered phase gap map to improve an estimate for a height profile of the test surface.

Abstract: A projection exposure apparatus includes an illumination optical system for illuminating a reticle having a pattern, with illumination light supplied from a light source, a projection optical system for projecting the pattern onto a substrate by use of the illumination light, a measuring system for measuring angular distribution of the illumination light, and an adjusting system for changing angular distribution of the illumination light, entering the projection optical system, on the basis of measurement by the measuring system and in accordance with a distance from an optical axis.

Abstract: The present invention provides a method of testing micro-electrical mechanical mirrors including simultaneously applying a voltage to each of a plurality of such mirrors to tilt each of the plurality to a deflection angle, and simultaneously deflecting a beam from each of the plurality using an interferometer to simultaneously determine an accuracy of the deflection angle of each of the plurality. In addition, a method of manufacturing micro-electrical mechanical mirrors is also disclosed.

Abstract: First and second connector housings (20, 26) each hold a corresponding set (22, 30) of numerous fibers, that are coupled when their tips (40, 42) abut, in a low-cost and rugged arrangement. The housings are identical and each has numerous bores (50, 52) extending to a mating face (34, 36). Each fiber is fixed in position in one of the bores, by potting material (64). The diameters of the bores are only slightly greater than the diameters of the fibers, so the potting material helps center the fiber in the end of the bore that lies adjacent to the mating face.

Abstract: An exposure device which includes a stage device having a first stage which movably supports an object and a drive mechanism which drives the first stage in at least a first direction. The first stage has a first portion coupled to the drive mechanism and a second portion for supporting the object. The first stage device is configured with a first position measuring device which measures the position of the first portion in a predetermined measurement direction. The exposure device further includes a first stage control system which controls the drive mechanism to control the position of the object in at least a first direction based on a measurement result obtained by the first position measuring device.

Abstract: A method for measuring two-dimensional displacement using conjugate optics comprises the steps of emitting an incident beam onto a diffraction element to generate many firstly diffracted beams, selecting two axially symmetric beams of the same order of diffraction from the firstly diffracted beams, introducing corresponding sets of wavefront reconstruction optics to reflect the two selected beams back onto the same incident spot along the same optical paths and to generate many secondly diffracted beams, selecting two axially symmetric pairs of beams of the same order of diffraction from the secondly diffracted beams, forming two interference fringes by superposing the two selected pairs of beams via corresponding mirrors and interferometric optics, and obtaining two linearly independent displacements of the diffraction element relative to the rest of the optics by decoding the two interference fringes.

Abstract: The invention concerns a method for identifying an object comprising the following steps: (a) selecting an intrinsic surface of an object to be identified; (b) illuminating at least an identification zone in the intrinsic surface of the object to be identified with a coherent light and intercepting at least part of the light reflected by the identification zone, so as to obtain an interference figure in specific illuminating and intercepting conditions; (c) preserving said interference figure as reference interference figure of the object to be identified; (d) placing a candidate object which could possibly be the object to be identified in similar illuminating and intercepting conditions as those used to obtain the reference interference figure and obtain from said candidate object an interference figure; (e) comparing the reference interference figure with the interference figure of the candidate object; and (f) assessing the probability of identity between the object to be identified and the candidate obje

Abstract: A system and method for non-linearity compensating interferometer position data includes receiving a plurality of groups of digital position values. A first group of the digital position values are digitally processed to generate a plurality of data values. The plurality of data values are digitally processed to generate at least one quasi-static non-linearity parameter. A second group of the digital position values are compensated based on the at least one non-linearity parameter.