Single-longitudinal-mode Nd-laser with a Bragg-grating Fabry-Perot cavity

Area of Science:

• Optics and Photonics
• Laser Physics
• Materials Science

Background:

• Single longitudinal mode (SLM) lasers are crucial for applications requiring high spectral purity.
• Nd:GdVO(4) (Neodymium-doped Gadolinium Vanadate) is a promising gain medium for solid-state lasers.
• Achieving SLM operation in lasers with longer cavity lengths can be challenging due to increased mode density.

Purpose of the Study:

• To demonstrate a compact and efficient laser system capable of stable single longitudinal mode operation.
• To investigate the use of a volume Bragg grating (VBG) as a key component for mode selection and tuning.
• To characterize the output power, spectral properties, and tuning range of the developed laser.

Main Methods:

• The laser cavity was constructed using a Nd:GdVO(4) gain medium and a volume Bragg grating in glass.
• A simple linear cavity design was employed, incorporating elements of a Fabry-Perot cavity and a narrowband filter.
• The VBG was utilized to enforce single longitudinal mode operation and enable wavelength tuning.

Main Results:

• The laser achieved an output power of 0.85 W in a single longitudinal mode at a wavelength of 1066 nm.
• Stable SLM operation was maintained for cavity lengths up to 8 mm, attributed to the narrowband VBG.
• A continuous tuning range of 25 GHz was demonstrated for shorter cavity lengths, albeit with reduced power.

Conclusions:

• A simple, two-component laser design utilizing a Nd:GdVO(4) gain medium and a VBG can effectively achieve high-power, single longitudinal mode operation.
• The VBG serves as a critical element for mode discrimination and wavelength tuning in compact laser cavities.
• The demonstrated performance highlights the potential of this laser configuration for various spectroscopic and photonic applications requiring narrow linewidths.