Low-threshold femtosecond optical parametric oscillator based on chirped-pulse frequency conversion

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Chirped-pulse techniques offer advantages in nonlinear frequency conversion.
• Aperiodic poling in materials like potassium titanyl phosphate (KTP) enables efficient nonlinear processes.

Purpose of the Study:

• To demonstrate the first femtosecond optical parametric oscillator (fs-OPO) utilizing chirped-pulse frequency conversion.
• To investigate the performance of a long, aperiodically poled potassium titanyl phosphate (APP-KTP) crystal in an fs-OPO.
• To characterize the threshold power, slope efficiency, and tuning range of the developed fs-OPO.

Main Methods:

• Fabrication of a long crystal of aperiodically poled potassium titanyl phosphate (APP-KTP).
• Implementation of a femtosecond chirped-pulse frequency conversion scheme within the APP-KTP crystal.
• Experimental measurement of pump threshold power, signal slope efficiency, and wavelength tuning range.

Main Results:

• Achieved a minimum pump threshold power of 15 mW.
• Demonstrated a signal slope efficiency of 35%.
• Obtained continuous wavelength tuning from 1190 to 1450 nm with 800 mW of average pump power.

Conclusions:

• The study successfully demonstrated a novel femtosecond OPO based on chirped-pulse frequency conversion in APP-KTP.
• The results highlight the potential of long APP-KTP crystals for efficient and tunable femtosecond pulse generation.
• This technology offers a promising platform for various applications requiring tunable ultrashort laser pulses.