Doppler-free three-photon resonant six-wave mixing
消多普勒三光子共振六波混频

We study the three-photon resonant six-wave mixing (SWM) with phase-conjugation geometry in Doppler system. The theoretical calculation indicates that the signal spectrum is Doppler-free when the laser line width is narrow. This technique provides a new spectroscopic tool for studying the highly excited atomic or molecular states with high resolution. It has advantages of uncritical phase matching condition, excellent spatial signal resolution and simple optical alignment.