Phase offset and polarisation flipping in diamond Raman lasers with intracavity second harmonic generation.

Area of Science:

• Laser physics
• Nonlinear optics

Background:

• Diamond Raman lasers are efficient sources for various applications.
• Intracavity second harmonic generation (SHG) can increase output power at shorter wavelengths.
• Optimizing laser performance requires understanding complex interactions within the cavity.

Purpose of the Study:

• To investigate factors influencing the power output of a diamond Raman laser with double-pass intracavity SHG.
• To analyze the impact of crystal temperature on laser power and efficiency.
• To identify methods for optimizing laser performance and stability.

Main Methods:

• Experimental investigation of laser power and efficiency.
• Theoretical modeling incorporating Gouy phase shift.
• Temperature scanning of the frequency doubling crystal through its phase-matching condition.

Main Results:

• Accurate modeling requires inclusion of the Gouy phase shift for the second-harmonic.
• Observed laser power 'drop-outs' attributed to polarization state flipping.
• Temperature scanning revealed optimal cavity conditions for phase offset and polarization stability.

Conclusions:

• Gouy phase shift is crucial for accurate modeling of double-pass SHG in Raman lasers.
• Polarization dynamics significantly affect laser power output.
• Temperature scanning is an effective method for optimizing diamond Raman laser performance with SHG.