Investigation of the spectral and energy characteristics of a pulsed optical parametric oscillator operating in the regime of external signal injection

Experimental and theoretical investigations were made of the operation of a singly resonant optical parametric oscillator made of a lithium niobate crystal and pumped by the fundamentalfrequency radiation from a YAG:Nd laser. An external signal was injected into the oscillator. When the source of this signal was another optical parametric oscillator utilizing a crystal of barium sodium niobate, it was possible to generate narrow-band radiation throughout the tuning range of the singly resonant lithium niobate oscillator: the output power obtained in this case was several times higher than that in the absence of injection and the spectral brightness of the radiation was 10³ times higher. This was achieved at the expense of a slight loss (< 10%) of the fundamental-frequency radiation used to pump the barium sodium niobate oscillator.