Anisotropic ZnS:Cr²⁺ crystal: material for compact and efficient mid-IR tunable lasers

Area of Science:

• Materials Science
• Optics and Photonics
• Solid-State Lasers

Background:

• Development of novel laser materials is crucial for advancing optical technologies.
• Chromium-doped II-VI semiconductors offer potential for mid-infrared laser applications.
• Anisotropic crystal growth is key to achieving polarized laser output.

Purpose of the Study:

• To synthesize a laser-quality anisotropic ZnS:Cr2+ crystal.
• To investigate the lasing performance of the developed ZnS:Cr2+ element.
• To demonstrate wavelength tunability of the ZnS:Cr2+ laser.

Main Methods:

• Prolonged hot isostatic pressing at high temperatures was employed for crystal growth.
• Longitudinal pumping at 1.94 µm was used to excite the ZnS:Cr2+ laser.
• A short-cavity laser design and Brewster element rotation were utilized for tuning.

Main Results:

• A laser-quality anisotropic ZnS:Cr2+ element was successfully fabricated.
• Lasing was achieved centered at 2.45 µm with a slope efficiency of approximately 78%.
• Continuous wavelength tuning from 2.35 µm to 2.52 µm was demonstrated.

Conclusions:

• The developed ZnS:Cr2+ crystal is a promising gain medium for mid-infrared lasers.
• High slope efficiency and broad tunability indicate significant potential for practical applications.
• The material processing and laser design are effective for achieving tunable laser emission.