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Absolutní frekvenční posuvy jodem stabilizovaných laserových etalonů zpusobené čistotou jodu absorpčních kyvet
Hrabina, Jan ; Jedlička, Petr ; Číp, Ondřej ; Lazar, Josef
Results of measurement of purity of a set of iodine cells for laser stabilization made at our institute are presented. The purity was tested by improved method based on measurement of induced fluorescence and evaluation by the Stern-Volmer formula. This method was improved by innovation of the fluorescence detection system by introducing compensation for the pumping laser spectral and power instabilities. Further the absolute frequencies of selected iodine hyperfine transitions were measured in direct laser frequency comparison performed with a set of iodine-stabilized Nd:YAG laser etalons with the reproducibility well below the kHz level. The results indicating the iodine cell purity are presented with relation to the absolute frequency shifts. This highlights the influence of iodine cell quality onto the stability and absolute frequency of lasers etalons and also shows the way towards improvements of the iodine cell manufacturing technology.
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Měření čistoty jódu v absorpčních kyvetách pro frekvenční stabilizaci laserů
Hrabina, Jan ; Petrů, František ; Jedlička, Petr ; Číp, Ondřej ; Lazar, Josef
In the contribution we present a system for measurement of iodine purity by means excitation of a selected strong transition, measurement of induced fluorescence and evaluation by the Stern-Volmer formula. The arrangement is based on a pumping Ar-ion laser tuned to the transition of interest but its linewidth far exceeds the transition. Frequency noise of the laser is effectivelly reduced by monitoring the fluorescence in a second, reference iodine cell and together with monitoring of the laser power enables cancelation of the frequency noise influence which generates errors by demodulating on the absorption profile. The level of the scattered light is subtracted as well. All the measured data are digitally processed and the experiment is fully computer controlled.
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Generace a detekce hyperpolarizovaného xenonu
Rychnovský, Jan ; Buchta, Zdeněk
We present the experimental results of generation and detection of hyperpolarized Xenon obtained by 4.7 T, 200 MHz magnetic resonance (MR) system. Xenon 129 was hyperpolarized by the spin-exchange with Rubidium pumped by extended cavity laser system based on a tunable high-power laser diode optimized for maximum efficiency of the optical pumping process. The application of the laser system is oriented to employment in an experimental arrangement for production of hyperpolarized gasses (HpG), namely Xenon. It is designed to operate in medical and industrial applications to come.
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New trends in the metrology of geometrical quantities
Lazar, Josef
The contribution deals with an overview of trends in modern fundamental dimensional metrology. This is since the introduction of the definition of metre derived from the vacuum speed of light the domain of laser optics and interferometry. The fundamental etalons of length are highly stable optical oscillators – lasers and the primary measurements of lengths are performed by interferometers. This overview covers the newest results of development of stabilized lasers and interferometry of high resolution in the sub-nanometre range especially concerning the results achieved at the Department of Coherence Optics of the Institute of Scientific Instruments of the ASCR in this field.
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