All-solid-state tunable continuous-wave ultraviolet source with high spectral purity and frequency stability

Area of Science:

• Atomic, Molecular, and Optical Physics
• Laser Physics and Photonics

Background:

• High-resolution spectroscopy demands highly frequency-stable and tunable light sources.
• Current ultraviolet (UV) light generation methods often face limitations in stability, tunability, or output power.

Purpose of the Study:

• To present a novel approach for generating highly frequency-stable, widely tunable, single-frequency continuous-wave (cw) UV light.
• To demonstrate the suitability of this UV light for high-resolution spectroscopic applications.

Main Methods:

• Employed sum-frequency generation (SFG) utilizing two solid-state laser sources within a single cavity resonant for both fundamental waves.
• Utilized a frequency-doubled continuous-wave (cw) Nd:YAG laser as a master laser, slaving the SFG cavity and a Ti:sapphire laser (or diode laser) to it.

Main Results:

• Generated UV radiation around 313 nm with 33-mW output power using a Ti:sapphire laser.
• Achieved 2.1-mW output power at 313 nm when using a diode laser.
• Demonstrated continuous tunability exceeding 15 GHz, sub-megahertz short-term frequency fluctuations, and long-term frequency drift below 100 MHz/h.
• Maintained stable operation for several hours.

Conclusions:

• The developed SFG approach provides a robust method for generating high-quality UV light.
• The generated UV light meets the stringent requirements for high-resolution spectroscopy due to its stability and tunability.
• The theoretical framework for optimized doubly resonant SFG is presented, supporting the experimental findings.