Observation of optical-radio frequency resonance in H2O using wide-band ruby laser spectroscopy

An attempt is made to detect the effect of intra-Doppler Stark splitting produced by an intense radio frequency field on the absorption spectrum of probing optical emission under conditions of a complex resonance of the optical and radio frequency fields and the corresponding transitions. In the experiment described here, absorption in H2O at 694.38 nm is recorded by a wideband intracavity laser spectrometer based on a ruby laser. An analysis of experimental data indicates that the observed narrowing and widening of the trough in the generation spectrum characteristic are caused by a complex optical-radio resonance involving a resonant summation of the amplitudes of the probabilities of weak optical and resolved radio frequency transmition between the M-sublevels of Stark splitting.