Continuous-wave, single-pass, single-frequency second-harmonic-generation at 266 nm based on...

Area of Science:

• Laser physics
• Nonlinear optics
• Materials science

Background:

• Continuous-wave (cw) deep ultraviolet (UV) radiation is crucial for various scientific applications.
• Efficient generation of deep UV light often requires complex setups or nonlinear crystals with specific properties.

Purpose of the Study:

• To implement and characterize a compact cascaded multicrystal scheme for efficient cw deep UV generation.
• To investigate the performance and stability of the system for potential applications.

Main Methods:

• Utilized a cascade of four single-pass second-harmonic-generation (SHG) stages in beta-barium borate (BBO) crystals.
• Employed a single-frequency cw green laser source at 532 nm as the pump.
• Systematically characterized and optimized each stage, including angular phase-matching acceptance bandwidth and spectral properties.

Main Results:

• Achieved a continuous-wave (cw) deep UV output power of 37.7 mW at 266 nm.
• Demonstrated high passive power stability of 0.12% root mean square (rms) over 4 hours.
• Performed theoretical calculations for SHG in the cascaded scheme and compared BBO with other crystals.

Conclusions:

• The compact cascaded multicrystal scheme offers an efficient and stable method for generating cw deep UV radiation.
• The study provides valuable insights into optimizing such systems and highlights the potential of BBO crystals for deep UV generation.