Single-mode near-infrared optical parametric oscillator amplifier based on periodically poled KTiOPO4

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Achieving narrow spectral bandwidths in OPOs is essential for various spectroscopic applications.
• Periodically poled materials like KTiOPO4 (PPKTP) offer efficient nonlinear frequency conversion.

Purpose of the Study:

• To develop a singly resonant, single-axial-mode optical parametric oscillator (OPO).
• To achieve narrow optical bandwidths for both signal and idler waves.
• To demonstrate efficient amplification of OPO output without spectral broadening.

Main Methods:

• Utilized a periodically poled KTiOPO4 (PPKTP) crystal in a singly resonant OPO configuration.
• Employed a diffraction grating at grazing incidence to narrow the signal and idler optical bandwidths to <400 MHz.
• Implemented a single-pass PPKTP amplifier to boost the generated signal and idler radiation.

Main Results:

• The OPO generated 370 microJ of signal radiation from 3.1 mJ of pump radiation at 1.064 microns.
• Signal (1.68 micron) and idler (2.90 micron) bandwidths were successfully narrowed.
• The single-pass amplifier increased signal to 2.15 mJ and idler to 1.17 mJ without spectral broadening.

Conclusions:

• A narrow-bandwidth, single-axial-mode OPO based on PPKTP was successfully realized.
• The implemented amplification scheme efficiently increased output power while preserving spectral characteristics.
• This work provides a robust platform for generating high-energy, narrow-linewidth parametric radiation.