Compact deep ultraviolet frequency-doubled Tb:LiYF₄ lasers at 272 nm

Area of Science:

• Laser Physics
• Nonlinear Optics
• Materials Science

Background:

• Deep ultraviolet (DUV) radiation is crucial for various scientific and industrial applications.
• Efficient generation of DUV lasers, particularly at specific wavelengths like 272 nm, remains a challenge.
• Intra-cavity frequency conversion techniques offer a pathway to enhance DUV laser performance.

Purpose of the Study:

• To develop a new laser system for generating coherent deep ultraviolet (DUV) radiation at 272 nm.
• To investigate both continuous-wave (cw) and Q-switched operations for DUV generation.
• To evaluate the potential of the system for high energy and peak power DUV output.

Main Methods:

• Intra-cavity frequency doubling of terbium-doped lithium yttrium fluoride (Tb3+:LiYF4) lasers emitting at 544 nm.
• Utilized a type I phase-matched beta-barium borate (β-BaB2O4) nonlinear crystal for frequency conversion.
• Employed cobalt-doped magnesium aluminate (Co2+:MgAl2O4) saturable absorbers for passive Q-switching.

Main Results:

• Achieved continuous-wave (cw) DUV output power of 127 mW at 272 nm.
• Demonstrated passive Q-switched operation yielding up to 7.6 µJ single-pulse energy and 6.1 W peak power.
• Further optimization with smaller transmittance resulted in 277 mW average DUV power, with potential for ~100 µJ pulse energy and ~320 W peak power.

Conclusions:

• Successfully developed a laser system capable of generating coherent DUV radiation at 272 nm.
• The system demonstrates efficient cw and Q-switched operation, highlighting versatility.
• The achieved results indicate significant potential for high energy and peak power DUV laser applications.