A spectrophotometer incorporating an interferometer and a dispersive system is adapted to have an enlarged inlet field without degrading its spatial resolution. To this end, spectral data deduced horn measurements performed by means of the interferometer are transferred into spectral data deduced from measurements per formed by means of the dispersive system. Such spectrophotometer makes it possible to scan an observation field quickly, and is compatible with use on board a satellite.

A spectroscopic detection system is described for monitoring ambient air for toxic chemical substances. The system can be a compact, portable multiple gas analyzer capable of detecting and discriminating a broad range of chemical constituents including various nerve and blister agents as well as toxic industrial chemicals at low or sub part per billion (ppb) levels. The system minimizes false alarms (e.g., false positives or negatives), features high specificity, and can operate with response ti...

A system for comparative interferogram spectrometry includes an interferometer configured to generate interferograms from incident radiation from a target region, an interferogram database containing stored interferograms, and a processing subsystem configured to receive the generated interferograms and compare the received interferograms to the stored interferograms.

An optical spectrum analyzer detects a light output that is dependent on the frequency of light in a wavelength range of light to be measured. The optical spectrum analyzer includes a waveguide acousto-optic tunable filter including a piezoelectric substrate, optical waveguides, and an IDT, a light source for providing, to the waveguide acousto-optic tunable filter, reference light having a particular wavelength outside the wavelength range, a driving circuit for providing, to the waveguide acou...

A method of absolute optical frequency measurement is realized by using mode-locked laser frequency combs to measure the optical frequency of an unknown laser. By varying the repetition frequency, the relative frequency location of the unknown laser to the beating comb line is determined according to the corresponding variation of the beat frequency. Also, by varying the offset frequency of the mode-locked laser, the real offset frequency detected by a self-referencing technique can be determine...

The invention relates to a confocal 4.pi. microscopy method which is characterized by coherently illuminating a sample from two sides by one objective each with illumination light which has at least one illumination wavelength whereby a stationary illumination wave having a main illumination maximum and secondary illumination maxima is produced by interference of the illumination light in the sample. The detection light emitted by the sample has at least one detection wavelength and is detected ...

A method and apparatus for detecting small shifts in optical wavelength is provided. Light having a known wavelength is directed towards a target volume in the atmosphere. Light reflected from the target volume is received and mixed with differentially delayed copies of itself to produce three interference signals. The interference signals are taken at delays spanning one-half the wavelength of the transmitted signal. The intensity of the signal at the three different delays is measured simultan...

A spectroscopic detection system is described for monitoring ambient air for toxic chemical substances. The system can be a compact, portable multiple gas analyzer capable of detecting and discriminating a broad range of chemical constituents including various nerve and blister agents as well as toxic industrial chemicals at low or sub part per billion (ppb) levels. The system minimizes false alarms (e.g., false positives or negatives), features high specificity, and can operate with response ti...

A photo-thermal interferometric spectroscopy system is disclosed that provides information about a chemical at a remote location. A first light source assembly is included that emits a first beam. The first beam has one or more wavelengths that interact with the chemical and change a refractive index of the chemical. A second laser produces a second beam. The second beam interacts with the chemical resulting in a third beam with a phase change that corresponds with the change of the refractive i...

The present invention provides an economically feasible robust spatial heterodyne spectroscopy (SHS) interferometer. A first type prior art monolithic SHS interferometer is exceedingly expensive, whereas a second type of prior art SHS interferometer is extremely large and has many components, which need to be tuned. The present invention is much less expensive than the first type of prior art SHS interferometer and is much smaller that the second type of prior art SHS interferometer.