Abstract:
Increased sensitivity of spectrometers through reducing noise in independent voltage signals via a differential voltage analyzer utilizing a reference wavelength from a wavelength region in which the optical absorption of the sample is negligible. In an embodiment, a grating permits selection of a reference wavelength. In another embodiment, filters permit selection of a reference wavelength. In yet another embodiment, both a grating and a filter permit selection of a reference wavelength. In an aspect, the differential voltage analyzer reduces noise by minimizing a differential voltage between the independent voltage signals and the reference voltage signal by adjusting the value of a cancellation coefficient.
Abstract:
A spectrometer includes an illuminating section; a receiving section configured to detect radiation reflected from an object including an optically inhomogeneous scattering medium; a hardware section configured to obtain a solution of an inverse problem to reconstruct an absorption spectrum of the optically inhomogeneous scattering medium, wherein the illuminating section includes at least one light-emitting diode source, a radiation spectral curve of which is divided, by at least two spectral filters having different spectral transmission curves, into at least two spectral regions, to form an equivalent radiation spectrum from at least two spectral sources, and wherein the hardware section applies the solution of the inverse problem based on information about a spectral content of the radiation of the illuminating section, a signal obtained in a form of a response from the optically inhomogeneous scattering medium, and a spectral sensitivity curve of the receiving section.
Abstract:
A spectrometer comprises a plurality of isolated optical channels comprising a plurality of isolated optical paths. The isolated optical paths decrease cross-talk among the optical paths and allow the spectrometer to have a decreased length with increased resolution. In many embodiments, the isolated optical paths comprise isolated parallel optical paths that allow the length of the device to be decreased substantially. In many embodiments, each isolated optical path extends from a filter of a filter array, through a lens of a lens array, through a channel of a support array, to a region of a sensor array. Each region of the sensor array comprises a plurality of sensor elements in which a location of the sensor element corresponds to the wavelength of light received based on an angle of light received at the location, the focal length of the lens and the central wavelength of the filter.
Abstract:
A system comprising a light source configured to illuminate a sample under measurement. The system includes a detector configured to receive reflected light from the sample, and the detector generates a signal representing the reflected light. A spatially variable filter (SVF) is positioned in the optical path. The SVF is configured to have spectral properties that vary as a function of illuminated position on the SVF.
Abstract:
A spectrometer comprises a plurality of isolated optical channels comprising a plurality of isolated optical paths. The isolated optical paths decrease cross-talk among the optical paths and allow the spectrometer to have a decreased length with increased resolution. In many embodiments, the isolated optical paths comprise isolated parallel optical paths that allow the length of the device to be decreased substantially. In many embodiments, each isolated optical path extends from a filter of a filter array, through a lens of a lens array, through a channel of a support array, to a region of a sensor array. Each region of the sensor array comprises a plurality of sensor elements in which a location of the sensor element corresponds to the wavelength of light received based on an angle of light received at the location, the focal length of the lens and the central wavelength of the filter.
Abstract:
Increasing the precision of process monitoring may be improved if the sensors take the form of travelling probes riding along with the flowing materials in the manufacturing process rather than sample only when the process moves passed the sensors fixed location. The probe includes an outer housing hermetically sealed from the flowing materials, and a light source for transmitting light through a window in the housing onto the flowing materials. A spatially variable optical filter (SVF) captures light returning from the flowing materials, and separates the captured light into a spectrum of constituent wavelength signals for transmission to a detector array, which provides a power reading for each constituent wavelength signal.
Abstract:
A spectrometer comprises a plurality of isolated optical channels comprising a plurality of isolated optical paths. The isolated optical paths decrease cross-talk among the optical paths and allow the spectrometer to have a decreased length with increased resolution. In many embodiments, the isolated optical paths comprise isolated parallel optical paths that allow the length of the device to be decreased substantially. In many embodiments, each isolated optical path extends from a filter of a filter array, through a lens of a lens array, through a channel of a support array, to a region of a sensor array. Each region of the sensor array comprises a plurality of sensor elements in which a location of the sensor element corresponds to the wavelength of light received based on an angle of light received at the location, the focal length of the lens and the central wavelength of the filter.
Abstract:
A spectral image acquiring device comprises an objective lens, a field aperture member for limiting a size of an image passing through the objective lens and focusing, a wavelength selecting member arranged on an optical axis of the objective lens, having two or more wavelength selecting surfaces and having different wavelength selection characteristics for each of the wavelength selecting surfaces, a deflecting member for deflecting partial luminous fluxes passing through the wavelength selecting surface, an image pickup element arranged on the optical axis of the objective lens, and an image forming lens for focusing the partial luminous fluxes deflected by the deflecting member on the image pickup element for each of the partial luminous fluxes.
Abstract:
An optical analyzer (14) for performing spectral analysis on an optical beam (18) includes an optical filter (28), a mover (30), an optical launcher (36), and an optical receiver (38). The optical filter (28) includes a filter area (46) that is a narrow band pass type filter having multiple alternative center bandwidths that are distributed along the filter area (46). The mover (30) moves the optical filter (28). The first optical launcher (36) directs the optical beam (18) at the filter area (46) so that the optical beam (18) is near normal incidence to the filter area (46). The optical analyzer (14) can be used to simultaneously monitor multiple optical signals. Additionally, the optical analyzer (14) can include a beam redirector (40) that causes the optical beam (18) to make two passes through the optical filter (28).
Abstract:
A new architecture for implementing a time-resolved Raman spectrometer is 2-3 orders of magnitude faster than current systems. In one embodiment, the invention employs a rotating optical switch to time multiplex an input signal through multiple band-pass filters and into a single optical detector which is electrically activated only when the filtered input light pulse is about to impact it.Time-multiplexing the input signal through multiple optical filters and time-sequencing the optical detector enables the device to detect and analyze 2-3 orders of magnitude faster than current designs. In one embodiment, the system may be employed for the diagnostics of a pathological condition of skin tissue in patients, such as malignant melanoma or other types of skin cancers and abnormal conditions.