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Proceedings Paper

Tunable blocking filter for laser bigarmonic spectrometer
Author(s): G. E. Kulikov
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Paper Abstract

The tunable blocking filter for the laser bigarmonic spectrometer is described. The filter prevents damage of the photoreciever CCD cells by the power optical beam. The calibration of the filter is performed by the automated procedure that speed - up the process and give the ability to check the adjustement of the interferometer of the filter avoiding it’s disassembling from the optical installation of the spectrometer. A group of laser spectroscopy specialists of the Institute of Atmospheric Optics has developed a laser spectrometer with a bigarmonic source for experimental investigation of the responce of molecular media exitied by bigarmonic optical field and verification of the hypothese about generation an optical field in these media. The spectrometer consists of: a) tunable laser based on two alumoittrium heads and frequency multiplicators, b) optical installation and gas probing cell, c) diffraction spectrograph (symbols available in paper) and linear CCD photoreceiver ILX-511, d) CAMAC modules, the computer and proper software. Peculiarity of described scheme consist in the necessity to register reemission coaxial with the pumping field. The wavelength of investigated reemission signal is close of the halfsum of the wavelength of the pumping bigarmonic. To avoid falling intense light on CCD device, which can physically damage photorecieving cells or, as minimum, completely mask usefull signal, it is necessary to mount an blocking optical filter into optical installation of the spectrometer. The filter have to provide continiuous blocking (when laser emitter tunes in diapasone of Δλ1,2 ≈ 18526 ± 4 cm-1) of the baffled components of the bigarmonic pumping. The present work is aimed to developing, preparing and testing such tunable rejecting filter. The Fabri - Perout interferometer was choosed as base element of the optical filter. The interferometer must be tuned to place next transmission maximum near the frequency of the investigating signal. In that way it is necessary to provide: a) optical conjugation of the interferometer with a gas probe cell and forming parallel optical beams, b) the possibility to tune the basis of the interferometer synchronously with the laser emitter tuning. To conjugate the interferometer with the cell and to form the proper optical beam, an optical scheme consisting from the lense L1 with the focal distance F1 = 150 cm, and the telescope T equipped with a microobjective was mounted before the interferometer. After the interferometer, an diaframe (formula available in paper) and the lense L2 with the focal distance F2 = 61 cm was mounted. Tuning of the interferometer (we’ve used an hook-up specimen of the interferometer by “NPO ANGSTREM”, Novosibirsk) is performed by constant voltage (0 ••• 150V) passed into piezoceramic plates. The voltage level is adjusted by the computer via CAMAC’s ADC device and voltage former. Sience given interferometer does not contain any thermo- and barostabilisaztion facilities and it’s parameters are greatly varying on time, it is not enough to adjust defined voltage level to operate with it. It is necessary to check interferometer’s adjustment and to prove it’s amplitude - frequency characteristics every time before working with the filter. The follows methodic and automated procedure are used in order to calibrate the filter and to proove the adjustments of the interferometer without it’s disassembling:

Paper Details

Date Published: 12 January 2004
PDF: 3 pages
Proc. SPIE 5311, 14th Symposium on High-Resolution Molecular Spectroscopy, (12 January 2004); doi: 10.1117/12.545713
Show Author Affiliations
G. E. Kulikov, Institute of Atmospheric Optics (Russia)


Published in SPIE Proceedings Vol. 5311:
14th Symposium on High-Resolution Molecular Spectroscopy

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