Coherent Raman beats associated with superhyperfine structure in ruby

Coherent Raman beats associated with superhyperfine structure (shfs) due to Cr-Al interaction were observed in ruby. The rf modulated Stark field was used to create coherences between shfs sublevels under the irradiation with a cw ruby laser. From the beat frequencies high resolution spectra of shfs with width (HWHM) of about 10 kHz were obtained in the frequency range from about 4.5 to 6.5 MHz. The utility of phase sensitive detection technique combined with rf Stark modulation was demonstrated. The observed spectra were compared with the theoretical ones.