Optical parametric oscillator with non-ideal mirrors and single- and multi-mode pump beams

Area of Science:

• Nonlinear Optics
• Laser Physics
• Quantum Optics

Background:

• Residual reflections of the idler wave in optical parametric oscillators (OPOs) can cause output fluctuations due to phase sensitivity.
• Pulsed OPOs are susceptible to these fluctuations, impacting their performance and stability.

Purpose of the Study:

• To experimentally and numerically investigate energy fluctuations in pulsed singly resonant optical parametric oscillators.
• To determine the effect of single- and multi-longitudinal mode pump beams on these fluctuations.
• To analyze the self-focusing effects associated with the parametric conversion process.

Main Methods:

• Experimental measurements of energy fluctuations in pulsed OPOs.
• Numerical simulations of the OPO system.
• Utilizing both single- and multi-longitudinal mode pump beams for comparison.
• Observing and quantifying self-focusing of the pump beam.

Main Results:

• Energy fluctuations are significantly reduced when using a multi-mode pump beam compared to a single-mode pump.
• The parametric conversion process induces substantial self-focusing of the pump beam.
• Self-focusing limits the maximum achievable pump energy, posing a constraint on OPO performance.

Conclusions:

• A multi-mode pump beam is preferable for reducing output fluctuations in OPOs, especially when unwanted reflections are present.
• Self-focusing is a critical factor limiting the operational energy of OPOs.
• Understanding these effects is crucial for optimizing OPO design and performance.