FREQUENCY DETERMINATION OF FAR-INFRARED OPTICALLY PUMPED LASER LINES OF VINYL FLUORIDE USING A NIOBIUM NITRIDE JOSEPHSON MIXER

Using the alternating current Josephson effect in a thin film niobium nitride (NbN) Josephson tunnel junction, we report the first accurate frequency measurements of optically pumped far infrared laser lines of vinyl fluoride (C2H3F) High harmonics of the local oscillator microwa ve source were mixed with the vinyl fluoride laser line in the junctio n and the intermediate frequency beat measured. The precise laser freq uencies, and their CO2 pump lines are 902.001 593(42) GHz, 10P6; 889.3 41 248(67) GHz, 10P38; 673.997 567(19) GHz, 10R20; 634.221 681(47) GHz , 10P20; 453.65259(11) GHz, 10P24; and 446.698886(30) GHz, 10P36. Thes e frequencies are currently being used to analyse laser magnetic reson ance spectra of the CF and CH2Br free radicals.