Synchronized retroreflection-pumped femtosecond optical parametric oscillator

Area of Science:

• Nonlinear Optics
• Laser Physics
• Quantum Optics

Background:

• Synchronously pumped optical parametric oscillators (SPOPOs) are crucial for generating tunable laser light.
• Improving SPOPO efficiency, particularly threshold reduction and output power, remains an active research area.
• Existing methods often involve complex setups or compromise pulse characteristics.

Purpose of the Study:

• To develop a flexible and effective technique for threshold reduction and output power enhancement in SPOPOs.
• To enable independent control over spatial and temporal overlap of the pump beam.
• To demonstrate the technique's efficacy without negatively impacting output pulse quality.

Main Methods:

• Implementing synchronized retroreflection of the undepleted pump beam using a collimating system and delay line.
• Utilizing interferometry for initial synchronization of forward and retroreflected pump beams before oscillation.
• Employing a femtosecond SPOPO based on BiB3O6 crystal for demonstration.

Main Results:

• Achieved a 22% reduction in oscillation threshold compared to single-pass pumping.
• Demonstrated a 70% enhancement in output power.
• Confirmed no detrimental effects on the spectral and temporal characteristics of the output pulses.

Conclusions:

• The synchronized retroreflection technique offers a versatile approach to significantly improve SPOPO performance.
• This method provides an easy and independent adjustment of pump beam overlap, crucial for efficient parametric generation.
• The demonstrated improvements in threshold and power, without compromising pulse quality, highlight the technique's practical applicability.