Room-temperature, rapidly tunable, green-pumped continuous-wave optical parametric oscillator

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Continuous-wave optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Existing OPOs often face limitations in tuning range, power, or stability.
• Developing compact, room-temperature tunable sources is essential for various spectroscopic applications.

Purpose of the Study:

• To report a novel high-power, single-frequency, green-pumped continuous-wave optical parametric oscillator (OPO).
• To demonstrate rapid and continuous spectral tuning across a wide near-infrared range at room temperature.
• To characterize the power, stability, and beam quality of the developed OPO system.

Main Methods:

• Utilized a magnesium oxide-doped periodically poled stoichiometric lithium tantalate (MgO:sPPLT) nonlinear crystal.
• Employed a fan-out grating design for wavelength tuning via mechanical translation.
• Pumped the OPO using a 532 nm green laser source.
• Operated the device at room temperature without active cooling.

Main Results:

• Achieved continuous idler tuning from 1097 nm to 2100 nm and signal tuning from 712 nm to 1033 nm.
• Delivered hundreds of milliwatts of idler power across the tuning range, with a maximum of 2.2 W at 1097 nm.
• Demonstrated high pump depletion (77%) and excellent power stability (<1% rms over 30 min).
• Measured signal frequency stability of 518 MHz over 2 min with an instantaneous linewidth of 6.9 MHz and high beam quality.

Conclusions:

• The developed MgO:sPPLT-based OPO provides a robust and versatile source for tunable near-infrared light.
• The device's high power, wide tuning range, and excellent stability make it suitable for advanced spectroscopic and photonic applications.
• This work advances the development of compact, room-temperature tunable laser sources.