Continuous-wave degenerate cavity laser for optical imaging in scattering media

Area of Science:

• Optics and Photonics
• Laser Physics

Background:

• High spatial coherence in lasers causes challenges like speckle noise and wavefront distortion.
• These issues limit laser applications in imaging and propagation through scattering media.

Purpose of the Study:

• To demonstrate a continuous-wave (cw) degenerate cavity laser (DCL) with low spatial coherence.
• To efficiently suppress the thermal lensing effect in the gain crystal.
• To provide a laser source suitable for speckle reduction and robust against atmospheric turbulence.

Main Methods:

• Utilized a degenerate cavity laser (DCL) design for continuous-wave (cw) operation.
• Focused on suppressing thermal lensing effects within the gain crystal.
• Experimentally characterized the laser output, including transverse mode count and speckle contrast.

Main Results:

• Achieved a cw degenerate laser output with approximately 2000 transverse modes.
• Demonstrated significantly reduced speckle contrast, measured at about 0.0224.
• Successfully suppressed the thermal lensing effect from the gain crystal.

Conclusions:

• The developed cw DCL offers low spatial coherence, mitigating speckle noise and wavefront distortion.
• The laser's robustness against atmospheric turbulence makes it suitable for laser imaging and illumination.
• This technology has potential applications in advanced laser imaging and optical illumination systems.