Japanese Journal of Applied Physics
Theory of Optical-Microwave Double Resonance. III. Double Resonance with Off-Resonant Optical Radiation
Michio Takami
Abstract
The theory of optical-microwave double resonance is extended to the case of the off-resonant optical field. Line shapes for fixed optical and variable microwave frequencies are calculated under various conditions by the density matrix method. Analytical expressions are given for small microwave or small optical saturation. When the off-resonance is much greater than the Doppler width of the optical transition, optical Stark effect and optical-microwave two-photon transition are the principal effects. When the signal is observed as a variation of microwave absorption, the former effect is much stronger than the latter. When the signal is detected optically, the two-photon and the stepwise transitions for small microwave saturation are the effects with the same order of magnitude, while the optical Stark effect is a secondary effect. The line shapes are also calculated numerically for arbitrary microwave and optical saturation.