Doppler-free Two-photon Absorption Research Articles

Doppler-free two-photon electronic absorption of nitric oxide and benzene

Doppler-free electronic state absorption spectra of molecules have been recorded by means of counterpropagating-beam two-photon spectroscopy. The molecular transitions that were investigated were the A2Σ+1(v=0) ←X2Π1/2 (v=0) transition of nitric oxide and the 1B2u←1A1g, 1410 transition of benzene. Linewidths observed were less than the Doppler width for each transition.

Observation of Doppler-Free Two-Photon Absorption in theν3Bands of CH3F

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