750 nm 1.5 W frequency-doubled semiconductor disk laser with a 44 nm tuning range

Area of Science:

• Optics and Photonics
• Laser Physics
• Materials Science

Background:

• Semiconductor disk lasers (SDLs) offer high power and good beam quality.
• Intracavity frequency doubling (IFD) is a method to generate shorter wavelengths from lasers.
• The 700-800 nm spectral range is important for biomedical imaging due to deep tissue penetration.

Purpose of the Study:

• To demonstrate high-power, tunable visible light generation from a semiconductor disk laser.
• To investigate the efficiency and beam quality of an intracavity frequency-doubled SDL.
• To assess the potential of this laser system for biomedical applications.

Main Methods:

• A wafer-fused semiconductor disk laser was diode-pumped at 980 nm.
• Intracavity frequency doubling was implemented using a bismuth borate (BiBO) crystal.
• An intracavity birefringent plate was used for wavelength tuning.
• The output power, optical-to-optical efficiency, and beam quality (M² parameter) were measured.

Main Results:

• 1.5 W of output power at 750 nm was achieved.
• An optical-to-optical efficiency of 8.3% was obtained.
• The doubled emission wavelength was tunable from 720 nm to 764 nm.
• The beam quality parameter M² was measured to be below 1.5 across all pump powers.

Conclusions:

• Intracavity frequency doubling of a diode-pumped semiconductor disk laser is an effective method for generating high-power, tunable visible light.
• The demonstrated laser system exhibits excellent beam quality and efficiency.
• This laser is a promising tool for biomedical applications, particularly those benefiting from the 700-800 nm spectral window for deep tissue penetration.