Longwave-IR optical parametric oscillator in orientation-patterned GaAs pumped by a 2 µm Tm,Ho:YLF laser

Area of Science:

• Optics and Photonics
• Materials Science
• Laser Physics

Background:

• Longwave infrared (LWIR) generation is crucial for various applications, including spectroscopy, sensing, and countermeasures.
• Optical parametric oscillators (OPOs) offer a versatile platform for generating tunable coherent light.
• Quasi-phasematching in nonlinear optical crystals enables efficient frequency conversion.

Purpose of the Study:

• To demonstrate efficient LWIR generation using an OPO based on quasi-phasematched orientation-patterned gallium arsenide (OPGaAs).
• To investigate the performance of an OPGaAs OPO pumped by a Tm,Ho:YLF laser.
• To explore the tunability and efficiency of LWIR output from the OPGaAs OPO system.

Main Methods:

• Fabrication of orientation-patterned gallium arsenide (OPGaAs) crystals with varying grating periods.
• Direct pumping of the OPGaAs OPO using a Q-switched 2.054 μm Tm,Ho:YLF laser.
• Characterization of the generated signal and idler wavelengths, output powers, and spectral properties.

Main Results:

• Successful generation of LWIR radiation (idler wavelengths from 8.8 to 11.5 μm) and signal wavelengths (2.5 to 2.7 μm).
• Achieved slope efficiencies up to 26% for combined signal and idler output, and 8% for idler-only output.
• Experimental results showed good agreement with theoretical predictions for spectral characteristics.

Conclusions:

• Orientation-patterned gallium arsenide is a viable material for efficient LWIR generation via optical parametric oscillation.
• The OPGaAs OPO system, pumped by a Tm,Ho:YLF laser, provides a robust method for accessing the LWIR spectrum.
• This work contributes to the development of advanced sources for LWIR applications.