Injection locking of the emission frequency of a pulsed dye laser with a compound resonator

An experimental investigation was made of a rhodamine 6G laser with injection of priming narrow-band radiation into a compound four-mirror resonator containing two active media pumped by radiation from one ruby laser. The priming narrow-band radiation was formed in a selective channel of the resonator by a phase–polarization method involving locking of the spectrum to the absorption lines of Na. The frequency locking efficiency was studied in a nonselective channel when the more powerful radiation was locked to the frequencies of the injected signal with a variable spectral composition. The efficiency was determined as a function of the parameters of the resonator and of the dye pumping system. Conditions for achieving a zero-background narrow-band emission spectrum were identified. The width of the main emission spectrum was reduced from 30 to 2 X 10^–3 nm without any loss in the output power.