A velocity servo for a continuous scan Fourier interference spectrometer of the double-pass retroreflector type having two "cat's eye" retroreflectors uses an open-loop, lead-screw drive system for one retroreflector with compensation for any variations in speed of drive of the lead screw provided by sensing any variation in the rate of reference laser fringes, and producing an error signal from such variation used to compensate by energizing a moving-coil actuator for the other retroreflector o...

An interferometer system for measuring the wavelength of laser light or and other optical radiation comprises an interferometer with a radiation input for a reference beam of a given wavelength, a sample radiation input for a sample beam of unknown wavelength, and a beam splitter for splitting up an incoming beam into two part-beams, and a system for changing the optical lengths of two part-beam optical paths as used by the reference beam and, parallel to it, the beam whose wavelength is to be m...

A refractively scanned interferometer, of the type in which a wedge-shaped prism is moved across one interferometer arm for scanning purposes, in which both the substrate of the beamsplitter and the scanning wedge are optically compensated for by substantially identical elements in the other arm of the interferometer.

A refractively scanned interferometer, of the type in which a wedge-shaped prism is moved across one interferometer arm for scanning purposes, in which a similarly shaped fixed prism in the other arm provides optical compensation to avoid aberration problems. The beamsplitter surface is on the fixed wedge-shaped prism, and the two wedge-shaped prisms constitute the only refractive elements in the interferometer arms.

A dual beam Fourier transform spectrometer produces two beams from a single infrared (IR) source. The beams are directed through a sample region, with one beam transiting a sample and the other beam transiting a reference cell. The sample and reference beams are then directed to a Michelson interferometer with cube corner retroflectors for optically cancelling the background signal from the separate sample and reference beams and for optically combining the sample and reference beams in an optic...

A wavemeter fabricated using integrated optics technology. A waveguide structure is formed in a substrate, the structure including signal and reference waveguides and means for coupling an optical input signal into both waveguides. Means are provided for varying the optical path length of the signal waveguide with respect to the reference waveguide in response to a control signal. Optical signals passing through the waveguides are coupled to a detection system that produces a feedback signal hav...

An interferometer with a cylindrical lens which produces an interferogram imaging the field of view in the redundant coordinate onto a photon noise limited detector comprising a charge-coupled device or CCD having pixels aligned along two dimensions to provide spatial resolution in that dimension of the light source as well as spectral resolution. The CCD is also characterized by greater dynamic range, lower pixel response variation, and is photon noise limited, all of which enhances its use as ...

An interferometer modulator (10) has a housing (12) that encloses a moving mirror (14) attached to a mirror arm (18) which is suspended by links (34, 36) from the housing (12). The links (34, 36) are attached to the mirror arm (18) at swinging pivots (42, 44) and are attached to the housing (12) at fixed pivots (46, 48). One of the fixed pivots (46) is mounted within an adjustable block (68) the position of which may be adjusted by the turning of adjust screws (82, 76). Turning of one of the adj...

An interferometer, for use in spectrometry, is disclosed in which a more reliable synchronization of the starting points of successive analytical scans is obtained by combining: (a) a moving retro-reflector in the variable-length arm which reflects both the analytical beam and the reference beam; (b) stationary reflecting means in the variable-length arm providing a flat "folding" reflector which causes the path of at least the reference beam from the retro-reflector to be folded on itself and r...

An on-line scanning sensor system includes first and second horizontally extending guide members connected by side members to define a rigid box-like frame, and a support structure for suspending the box-like frame via vibration-absorbing devices such that vibrations are substantially attenuated before reaching the guide members. Further, the system includes a carriage mounted on the first guide member for scanning motion across a traveling web of sheet of material, and interferometer components...