Frequency-modulation optical-optical triple-resonance optical heterodyne spectroscopy

We propose new frequency-modulation optical-optical triple-resonance (FM-OOTR) optical heterodyne spectroscopy, which can eliminate the Doppler-background in the recently developed optical-optical triple-resonance (OOTR) spectroscopy and provide improved resolution and sensitivity. Theoretical considerations and line shape calculations are presented. The potential applications of FM-OOTR technique to laser frequency stabilization with significant advantages can be expected.