Abstract:
Various systems and methods for performing optical analysis downhole with an interferogram (a light beam having frequency components with a time variation that identifies those frequency components. The interferogram is produced by introducing an interferometer into the light path, with the two arms of the interferometer having a propagation time difference that varies as a function of time. Before or after the interferometer, the light encounters a material to be analyzed, such as a fluid sample from the formation, a borehole fluid sample, a core sample, or a portion of the borehole wall. The spectral characteristics of the material are imprinted on the light beam and can be readily analyzed by processing electronics that perform a Fourier Transform to obtain the spectrum or that enable a comparison with one or more templates. An interferometer designed to perform well in the hostile environments downhole is expected to enable laboratory-quality measurements.
Abstract:
The invention relates to a spectrograph (11) comprising a waveguide (10) provided with accesses (10; 10b, 12), a means for injecting two guided contra-propagative waves by each accesses in such a way that a spatial interference is formed in the waveguide, means (19, 20, 14, 16) for detecting the energy of the evanescent wave of the guided field produced by the interference of said contra-propagative waves.
Abstract:
A Micro Electro-Mechanical System (MEMS) spectrometer architecture compensates for verticality and dispersion problems using balancing interfaces. A MEMS spectrometer/interferometer includes a beam splitter formed on a first surface of a first medium at an interface between the first medium and a second medium, a first mirror formed on a second surface of the first medium, a second mirror formed on a third surface of the first medium and balancing interfaces designed to minimize both a difference in tilt angles between the surfaces and a difference in phase errors between beams reflected from the first and second mirrors.
Abstract:
The invention relates to a Fourier transform spectrometer comprising a binary grating with variable depth, the grating comprising a first set of mirrors and a second set of mirrors, the mirrors of the first set of mirrors and the mirrors of the second set of mirrors being arranged in an alternating order and at least one of the sets of mirrors being carried by fingers of a comb structure of a wafer, the spectrometer further comprising an actuator for prompting a motion of the second set of mirrors and a detector for detecting a radiation reflected by the grating, the mirrors being orientated in a plane defined by said wafer and said motion of the second set of mirrors being given by a translation in a direction vertical to said wafer plane.
Abstract:
A spectrometry device comprising at least one wavefront-dividing interferometer comprising at least two unbalanced arms and at least one air wedge, a device for imaging interference fringes, an imaging sensor of the fringes and a processor that processes a signal derived from the sensor.
Abstract:
The Miniature Fourier Transform Spectrophotometer provides the capability, in a miniaturized device, of determining the light absorption/transmission spectra of a collected sample of gas or liquid though Fourier Transform spectroscopy techniques. The device takes an optical input from an optical fiber, manipulates that light through miniature optical components, and launches it into a miniaturized Michelson interferometer with a scanning mirror that acquires the interferogram of the optical input. The interferogram can be processed to retrieve the spectrum of the input light. A novel multi-stepped micro-mirror operates as the optical path length modulator in the miniaturized interferometer. A unique monolithic beamsplitter/mirror combination provides for accurate alignment of the components and greatly simplifies product integration. The device is designed to cover various optical spectra of interest. During operation, the precision and accuracy of the microfabricated components in the device allow operation and resolution even at extremely low wavelengths. In addition, the miniaturized nature of the device allows it to be used in new and extremely space-constrained applications.
Abstract:
A spectroscopic method and system for the spectral analysis of an optical signal directed to a wavelength dispersive component having two interleaved dispersive devices. For a single wavelength, the optical signal exiting the interleaved dispersive devices includes two wavefronts generally disposed at an angle to one another and producing an interference pattern. The interference pattern is detected and subsequently analyzed via a Fourier transform to produce the optical spectrum of the input beam. The method and system are applicable in a planar waveguide environment, in reflection and transmission geometries.
Abstract:
In general, the invention relates to the design and fabrication of optical devices suitable for use in methods and systems associated with phase-shift interferometry.
Abstract:
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.
Abstract:
One embodiment relates to an analyzer having an interferometer, a detector and a microprocessor, wherein the analyzer does not contain a spectrometer having a dispersive grating, the interferometer is to create a phase shift in an original spectrum of electromagnetic radiation emitted from a sample and Fourier transform the original spectrum to a Fourier transform spectrum, the detector is to detect a characteristic of the Fourier transform spectrum, and the microprocessor comprises software or a hardware to inverse transform the Fourier transform spectrum and reproduce the original spectrum. Another embodiment relates to a Raman analyzer having an interferometer, wherein the Raman analyzer contains no dispersive grating or moving parts and has an ability to analyze a Raman signal. The embodiments of the invention could be used for analyzing a sample by striking a laser to the sample and examining the spectrum of the emitted electromagnetic radiation from the sample.