Abstract:
A dual beam acousto-optic tunable spectrometer utilizes an optics system to isolate the two radiation beams tuned by an acousto-optic filter, one of which is used to analyze a sample, the other of which is used as a reference. The tuning of the filter and the analysis of the signals is conducted by a microprocessor, which corrects for the many possible sources of noise. A new fluid sample cell utilizing glass balls to collimate radiation incident on the sample and focus radiation transmitted from the sample, is also disclosed.
Abstract:
The invention is directed to an acousto-optic dispersive light analyzer (AODLF) which is an electronically adjustable spectroscopic device capable of instantaneously monitoring many wavelengths with a fixed drive frequency. The AODLF has about a one octave range, whose center is selected by changing the RF. The resolution of the AODLF in the infrared is several thousand, and it is electronically adjustable. The acousto-optic device according to this invention is particularly useful for the detection and analysis of short light pulses.
Abstract:
An improved acousto-optic tunable filter infrared analyzer system useable in a variety of industrial and commercial combustion control applications includes an acousto-optic tunable filter having a crystalline material selected from the group consisting of mercurous chloride, mercurous bromide and mercurous iodide. Selectively polarized infrared radiation is passed at a predetermined plane of incidence to the crystal axis, which plane contains both the (110) and (001) axes. The system relies upon a narrow band pass tunable acousto-optic filter which is selectively tuned by predetermined rf frequency signals to selectively transmit the narrow band pass of interest which corresponds to a specific molecular species for identification and analysis. The system includes a microcomputer and associated memory function to measure and compare detected signals from an infrared detector which converts the filtered infrared signal to an electrical signal. The memory provides control signals for the computer and for controlling the sequence and frequency of rf energy applied to tune the filter. In this way, the near to far range infrared can be analyzed for absorption bands corresponding to predetermined molecular species such as combustion product gases, and a feedback signal generated to control the combustion process.
Abstract:
An automated acousto-optic tunable filter infrared analyzer system useable in a variety of industrial and commercial control applications. The system relies upon a narrow band pass tunable acousto-optic filter which is selectively tuned by predetermined rf frequency signals to selectively transmit the narrow band pass of interest which corresponds to a specific molecular species for identification and analysis. The system includes a microcomputer and associated memory function to measure and compare detected signals from an infrared detector which converts the filtered infrared signal to an electrical signal. The memory provides control signals for the computer and for controlling the sequence and frequency of rf energy applied to tune the filter. In this way, the near to mid range infrared can be analyzed for absorption bands corresponding to predetermined molecular species such as combustion product gases, and a feedback signal generated to control the combustion process.
Abstract:
An acousto-optic RF spectrum analysis method and apparatus is disclosed wherein radio frequency energy to be spectrum analyzed is employed to excite an acoustic wave in an optically anisotropic medium. A linearly polarized white light beam is collinearly diffracted on the acoustic wave in the anisotropic medium to diffract light of the first polarization and of a frequency related to the frequency of the acoustic wave into light of the second polarization. The diffracted output light is then analyzed to separate light of the first polarization from light of the second polarization. The separated light is spectrum analyzed to obtain a spectrum corresponding to the spectrum of the radio frequency energy to be analyzed.
Abstract:
An acousto-optic light spectrum analysis method and apparatus is disclosed. A linearly polarized unknown light beam to be spectrum analyzed is collinearly diffracted on an acoustic wave in an optically anisotropic medium to diffract light of the first linear polarization and of a frequency related to the frequency of the acoustic wave into light of a second polarization. The diffracted unknown light beam is polarization analyzed to separate the light of the second polarization from the light of the first polarization. The frequency of the acoustic wave is swept and the light of the second polarization is detected as a function of the sweep to obtain a spectrum analysis of the unknown light beam. The output spectrum of the unknown light beam is calibrated by switching a known light source through the acousto-optic system for calibration of the output spectrum.