Abstract:
Light dispersing device comprising a slit element having a slit for exposure to electromagnetic radiation, wherein the slit element is configured and disposed for turning the slit between at least two positions. The light dispersing device is used together with a streak camera, whereby in a first position the slit is adjusted to influence the temporal resolution of the streak camera and in a second postion the slit is adjusted to influence the spectral resolution of the streak camera.
Abstract:
A sensor for measuring at least selected component in a composition can include: (a) a broadband light source, (b) an acousto-optic tunable filter (AOTF), (c) means for generating a beam of light from the light source and directing the beam of light at the AOTF wherein the AOTF is tuned to pass detection light having a desired wavelength range to detect the presence of the at least one component in the composition, (d) means for directing the detection light of known wavelength to the composition, (e) detection means for receiving light that emerges from the composition, and (f) a control signal generator configured to provide the AOTF with at least one desired wavelength range that is characteristic of the least one component in the composition. As an example, the sensor can be used to measure the thickness of optically transparent films.
Abstract:
The development of a multiple-channel dual phase lock-in optical spectrometer (LIOS) is presented, which enables parallel phase-sensitive detection at the output of an optical spectrometer. The light intensity from a spectrally broad source is modulated at the reference frequency, and focused into a high-resolution imaging spectrometer. The height at which the light enters the spectrometer is controlled by an acousto-optic deflector, and the height information is preserved at the output focal plane. A two-dimensional InGaAs focal plane array collects light that has been dispersed in wavelength along the horizontal direction, and in time along the vertical direction. The data is demodulated using a high performance computer-based digital signal processor. This parallel approach greatly enhances (by more than 100×) the speed at which spectrally resolved lock-in data can be acquired.
Abstract:
A system for spectral analysis of a multi-wavelength signal is disclosed. The illustrative embodiment of the present invention, like the prior art, uses a grating or prism to disperse the spectral components of a multi-wavelength signal, and then uses a reciprocating or rotating mirror to direct the spectral components, one at a time, into a photodetector. The illustrative embodiment uses a telescope between the grating and the mirror to improve the spectral resolution of the system.
Abstract:
A method for spectral analysis of the light proceeding from a specimen using a multi-band detector comprises the steps of defining an overall spectral region; from the overall spectral region, defining a first spectral subregion and defining at least a second spectral subregion; simultaneously detecting the light proceeding from the specimen in the first and the second spectral subregion, and generating detection values; displacing the first spectral subregion and displacing the second spectral subregion within the overall spectral region; and repeating steps c) and d) until the light has been detected over the entire overall spectral region.
Abstract:
Photometric detector assembly which includes a housing, means for passing an optical beam along a path through the housing to a detector, a NIST traceable calibration filter enclosed within the housing, and a remotely operable actuator for moving the filter into and out of the beam path.
Abstract:
A mirror driving mechanism comprises a driver configured to drive at least one mirror which reflects a light flux while adjusting a wavelength width and a wavelength band of the light flux separated in a spectrum, and a controller configured to control the driver.
Abstract:
A wavelength variable light source emits a light whose wavelengths continuously change from a preset start wavelength up to a stop wavelength to a measuring object. A timing information output section generates timing information showing emission timings of lights emitted from the wavelength variable light source and having start and stop wavelengths and a plurality of wavelengths obtained by delimiting the wavelengths between the start and stop wavelengths in predetermined steps. A light receiving section receives the light output from the measuring object and outputs a signal showing a measured value of a received light. A plurality of amplifiers receive the signal output from the light receiving section and amplify the signal at each predetermined amplification factor. A signal selecting section selects one signal kept in a predetermined measuring range of signals amplified by the plurality of amplifiers at the each predetermined amplification factor and outputs the one signal as a measured value of a light of a wavelength decided in accordance with corresponding timing information in the information output from the timing information output section.
Abstract:
The present invention relates to spectroscopic methods and systems for collecting electromagnetic radiation from an object using a continuously-spinning wavelength-selecting (CSWS) device, e.g., an interference filter(s)?? or grating. One embodiment of the invention provides a spectroscopic system for collecting electromagnetic radiation from a target. The spectroscopic system has at least one beam of electromagnetic radiation that interacts with the target. The system includes a continuously spinning wavelength-selecting (CSWS) device, e.g., a continuously spinning interference filter/grating driven by a DC motor, in the path of the at least one beam. The device filters the radiation with regard to wavelength to produce filtered radiation. The system further includes at least one detector in the path of the at least one beam for detecting the filtered radiation.
Abstract:
A plane diffraction grating based on surface normal rotation according to the present invention is designed so that the profile of the grooves at a radial area is determined depending on a rotational position of the area about a rotational center defined as a foot of the rotational axis on the surface of the plane diffraction grating. An optical system such as a spectrometer or a monochromator according to the present invention uses such a plane diffraction grating, and requires a special arrangement. The optical system includes: a plane diffraction grating as described above; a mechanism for rotating the plane diffraction grating about the rotational axis; an incidence optical system for casting a converging beam of light on a point of the surface of the plane diffraction grating, where the point is set apart from the rotational center. As the diffraction grating is rotated about the rotational center, the point on which the incident converging beam of light is cast rotates about the rotation center, where the diffracting condition is optimized anywhere around the rotational center or for any scanning wavelength. The surface of the plane diffraction grating can be covered with a multiple-layer coating to improve diffraction efficiency. When such a multiple-layer is coated, the unit thickness of the multiple-layer coating at an area is also determined depending on the rotational position of the area about the rotational center.