Development of high power, twin frequency far-infrared lasers for fusion diagnostics

Recent developments in plasma diagnostics such as multichannel collective scattering and phase imaging dictate the use of high-power, stable radiation sources in the far-infrared (FIR) spectral region. Towards this end, an optically pumped, twin frequency laser has been developed at UCLA. The CO2 pump laser produces greater than 100 W in a single mode over the majority of the CO2 wavelength range (9-11 μm). The twin frequency FIR laser utilizes a single cavity with two separate dielectric waveguides. The difference frequency (λ = 185 μm) is tunable from 0-5 MHz with a short-term stability Δ f ≤ +/- 20 kHz. EH11 spatial modes are routinely achieved with output powers of 100 mW