Injection-seeded intracavity terahertz optical parametric oscillator

We report a terahertz (THz) source continuously tunable over similar to 20 GHz with a linewidth <100 MHz (close to the transform limit of 1-10 ns pulses) and settable anywhere in the range of 1-3 THz. The source consists of an injection-seeded intracavity THz optical parametric oscillator, which exhibits the benefits of lower threshold and enhanced efficiency and power over a similar extracavity device. Linewidth control was achieved with <1 mW of seed laser power and THz pulse energies of >5 nJ observed with up to 68% downconversion of the pump wave. Spectroscopy of the 1.4969 THz carbon monoxide absorption line was performed to verify linewidth and demonstrate tuning capability (C) 2009 Optical Society of America