Tunable twisted-mode Ho:YAG laser at continuous-wave and pulsed operation

Area of Science:

• Laser Physics
• Solid-State Lasers
• Photonics

Background:

• Single-longitudinal-mode lasers are crucial for applications requiring high spectral purity.
• Ho:YAG lasers offer efficient operation in the mid-infrared region, suitable for various applications.
• Twisted-mode cavities provide a method for achieving single-mode operation in lasers.

Purpose of the Study:

• To demonstrate a single-longitudinal-mode Ho:YAG laser with a twisted-mode cavity.
• To investigate the performance of the laser in both continuous-wave (CW) and pulsed operation.
• To evaluate the wavelength tunability and beam quality of the developed laser system.

Main Methods:

• A Ho:YAG crystal was incorporated into a twisted-mode laser cavity.
• Continuous-wave and pulsed operation regimes were explored.
• An etalon was used for wavelength tuning, and an electro-optic switch enabled pulsed operation.
• Beam quality was assessed using M² factor measurements.

Main Results:

• Maximum CW single-longitudinal-mode output power of 0.76 W at 2097.46 nm with 28.9% slope efficiency was achieved.
• Wavelength tuning from 2096.94 nm to 2098.48 nm was accomplished using a 0.5-mm-thick etalon.
• Single-frequency pulsed operation yielded 0.2 mJ pulse energy at 2 kHz repetition frequency with a 116.5 ns pulse width.
• Excellent beam quality was confirmed with M² values of 1.15 (x-direction) and 1.10 (y-direction).

Conclusions:

• The twisted-mode cavity effectively enables single-longitudinal-mode operation in Ho:YAG lasers.
• The demonstrated laser exhibits promising performance for CW and pulsed applications requiring spectral purity.
• The tunable wavelength and good beam quality make this laser system suitable for various spectroscopic and sensing applications.