Phase-mismatched optical parametric oscillators based on aperiodic quasi-phase-matched crystals

Area of Science:

• Nonlinear optics
• Laser physics
• Materials science

Background:

• Femtosecond optical parametric oscillators (OPOs) are crucial for generating ultrashort light pulses.
• Achieving widely tunable and transform-limited pulses from OPOs remains a challenge.
• Aperiodic quasi-phase-matched (AQPM) crystals offer unique nonlinear optical properties.

Purpose of the Study:

• To investigate the operation of femtosecond OPOs in the phase-mismatched region using AQPM crystals.
• To demonstrate the generation of wavelength-tunable, transform-limited femtosecond pulses.
• To present a concise scheme for producing chirp-free femtosecond optical pulses.

Main Methods:

• Configuring femtosecond OPOs with AQPM crystals to operate in the phase-mismatched regime.
• Utilizing the phase-mismatch-induced frequency chirp from subcrystals.
• Optimizing intracavity group velocity dispersion and crystal orientation.
• Employing an all-normal-dispersion cavity design.

Main Results:

• Demonstrated generation of wavelength-tunable femtosecond pulses from 1520-1660 nm.
• Achieved transform-limited optical pulses by adjusting cavity length.
• Successfully suppressed unwanted chirp through optimized dispersion and crystal selection.

Conclusions:

• Femtosecond OPOs based on AQPM crystals can be operated in the phase-mismatched region to produce tunable, chirp-free pulses.
• This scheme provides a unique and concise method for generating widely tunable, transform-limited femtosecond optical pulses.
• The presented approach simplifies the production of high-quality femtosecond pulses for various applications.