Abstract:
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We report a continuous-wave (cw) source of tunable mid-infrared radiation providing tens of milliwatt of output
power in the 6460–7517 nm spectral range. The source is based on difference-frequency generation (DFG) in orientation-patterned
(OP)-GaAs pumped by a Tm-fiber laser at 2010 nm and a 1064 nm-Yb-fiber-pumped cw optical
parametric oscillator. Using a 25.7-mm-long OP-GaAs crystal, we have generated up to 51.1 mW of output power at
6790 nm, with >40 mW and >20 mW across 32% and 80% of the mid-infrared tuning range, respectively, which is to
the best of our knowledge the highest tunable cw power generated in OP-GaAs in this spectral range. The DFG
output at maximum power exhibits passive power stability better than 2.3% rms over more than 1 h and a frequency
stability of 1.8 GHz over more than 1 min, in high spatial beam quality. The system and crystal performance at high
pump powers have been studied |