ABSTRACT
A spatially resolved optical diagnostic for GaCl is described. The technique uses 248-nm excimer laser radiation to photolyze GaCl and also to excite fluorescence in the resulting gallium atoms. This yields gallium fluorescence at 245, 266, 287, 294, 403, and 417 nm. The method is specific to GaCl(3) and is not affected by the presence of a GaCl3 precursor. Gallium fluorescence is linear in both the GaCl partial pressure and the laser energy under specified conditions. The photophysics of this process are contrasted to related GACl studies of dissociative excitation at 193 nm.
ABSTRACT
A simplified method for measuring the effective photon lifetime in an optical resonator was developed. The technique requires the passage of a modulated cw laser beam through the resonator and the measurement of the resultant shift in the phase of the transmitted intensity. The method not only permits a quick and precise measurement of the mirror reflectances, but also permits these measurements to be in situ. Such an on-the-spot evaluation capability should be extremely useful in applications ranging from the investigation of new laser systems to the development of improved optical coatings. The method is also sensitive to the effects of absorption, scattering, and transmission from elements in the cavity. Cavity losses <100 ppm were detected.
ABSTRACT
A ratiometric system for accurately determining the percent O(2)((1)Delta) in a low-pressure gas sample has been developed and calibrated by use of a secondary microwave standard source and EPR measurements. The advantages of the new system over EPR are low cost and the ability to continuously monitor rapidly changing concentrations of O(2)((1)Delta).
ABSTRACT
Low pressure dilute diffusion flames of the metal-oxidation (M + N(2)O) and chain reaction (M + N(2)O + CO) types have been studied in absorption by means of modulated intracavity resonance spectroscopy. The measurements obtained were comparable in sensitivity to the intracavity dye laser technique but were of lower spectral resolution. The modulation experiment which is described herein has the advantage of measuring linearly and in real time the transmission factor gamma free from adverse anomalous dispersion effects. It is therefore well suited to the determination of electronic state densities. In these measurements, theground states of CaO and SrO were not detected, but the excited (1)pi and (3)pi states absorbed measurably and as a function of CO content in the flames.
