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Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
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Continuous-wave, multimilliwatt, mid-infrared source tunable across 6.4-7.5 μm based on orientation-patterned GaAs.
Optics Letters
|December 10, 2014
Summary
A new tunable mid-infrared laser source offers tens of milliwatts of continuous-wave power. This difference-frequency generation (DFG) system in orientation-patterned gallium arsenide (OP-GaAs) achieves record output for mid-infrared applications.
Area of Science:
- Optics and Photonics
- Laser Physics
- Materials Science
Background:
- Mid-infrared (MIR) radiation is crucial for spectroscopy and sensing.
- Generating tunable, high-power continuous-wave (cw) MIR sources remains challenging.
- Orientation-patterned (OP) semiconductors offer a promising platform for nonlinear frequency conversion.
Purpose of the Study:
- To develop and characterize a novel cw tunable MIR source.
- To demonstrate high output power and stability in the 6460-7517 nm range.
- To investigate the performance of OP-GaAs for difference-frequency generation (DFG).
Main Methods:
- Difference-frequency generation (DFG) in a 25.7-mm-long OP-GaAs crystal.
- Pumping the OP-GaAs with a 2010 nm Tm-fiber laser and a 1064 nm Yb-fiber-pumped cw optical parametric oscillator (OPO).
- Characterizing output power, tuning range, power stability, and frequency stability.
Main Results:
- Achieved up to 51.1 mW output power at 6790 nm.
- Generated >40 mW and >20 mW across 32% and 80% of the MIR tuning range, respectively.
- Demonstrated passive power stability <2.3% rms (1h) and frequency stability 1.8 GHz (1 min) with high beam quality.
Conclusions:
- This OP-GaAs based DFG system represents the highest tunable cw power source in this MIR spectral range to date.
- The demonstrated performance highlights the potential of OP-GaAs for robust MIR light generation.
- Further studies on system and crystal performance at high pump powers were conducted.
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