Detection of Raman amplification lines by intraresonator laser spectroscopy

The intraresonator laser spectroscopy method made it possible to increase the sensitivity of detection of weak absorption and amplification lines by five or six orders of magnitude. The application of this method revealed weak lines of Raman amplification in dichloroethane with vibrational frequencies ν_ν = 653, 676, and 753 cm^–1 and in gaseous acetylene with ν_ν = 1957 cm^–1. These Raman lines were excited by ruby laser radiation and were observed in the stimulated emission bands of cryptocyanine and DTTC.