Observation of doppler-free two-photon absorption in the. nu. /sub 3/ bands of CH/sub 3/F. [CO/sub 2/ laser excitation]

摘要: We report the first observation of Doppler-free two-photon absorption in a molecule using two fixed-frequency infrared optical fields combination with molecular Stark tuning. The coincidences $P14$ and $P30$ lines oppositely directed cw C${\mathrm{O}}_{2}$ lasers at 9.4 \ensuremath{\mu}m $R{(1, 1)}_{0\ensuremath{\rightarrow}{\ensuremath{\nu}}_{3}}$ $R{(2, 1)}_{{\ensuremath{\nu}}_{3}\ensuremath{\rightarrow}2{\ensuremath{\nu}}_{3}}$ $^{12}\mathrm{C}$${\mathrm{H}}_{3}$F are used to measure pressure-broadening coefficient ($\ensuremath{\Delta}{\ensuremath{\nu}}_{p}=41.3\ifmmode\pm\else\textpm\fi{}1.0$ MHz/Torr) pressure shift ($\ensuremath{\Delta}{\ensuremath{\nu}}_{s}=2.1\ifmmode\pm\else\textpm\fi{}0.1$ $0\ensuremath{\rightarrow}2{\ensuremath{\nu}}_{3}$ transition.