ABSTRACT
This paper presents measured data on mid-infrared filters using conducting elements based on a simple first-order design philosophy. To the best of our knowledge, the filter center frequencies are at least a factor of 10 higher than any previously reported. The use of conducting elements adds an additional degree of freedom, which may be exploited to obtain filter characteristics superior to simple multilayer dielectric filters.
ABSTRACT
In this paper we report the results of a series of pressure-broadened water vapor absorption measurements at 27 CO(2) laser frequencies between 935 cm(-1) and 1082 cm(-1). Both multiple traversal cell and optoacoustic (spectrophone) techniques were utilized together with an electronically stabilized cw CO(2) laser. Comparison of the results obtained by these two methods shows remarkable agreement, indicating a precision which has not been previously achieved in pressure-broadened studies of water vapor. The data of 10.59 microm substantiate the existence of the large (>200) self-broadening coefficients determined in an earlier study by McCoy. In this work we have treated the case of water vapor in N(2) at a total pressure of 1 atm. We have also studied water vapor in air and will report those results separately.
ABSTRACT
We have measured the monochromatic transmittances of pressure-broadened room-temperature water vapor samples at five laser frequencies of the CO(2) laser in the 10.4-microm band. Three different buffer gases were used. They were pure nitrogen, an 80:20 mixture of nitrogen and oxygen, and a 60:40 mixture of nitrogen and oxygen. The measurements at the five laser lines imply that oxygen is a less efficient broadener than nitrogen. The ratio of the oxygen-broadening coefficient to the nitrogen-broadening coefficient was measured to be 0.75 based on the data at the R(20) laser line. Results of this study demonstrate that pure nitrogen should not be used as a broadener for atmospheric modeling of monochromatic transmittances in the laboratory.
