Broadband, high-power, continuous-wave, mid-infrared source using extended phase-matching bandwidth in MgO:PPLN

Area of Science:

• Optics and Photonics
• Laser Physics
• Nonlinear Optics

Background:

• Continuous-wave (cw) mid-infrared (mid-IR) radiation sources are crucial for various applications.
• Existing sources often face limitations in power, bandwidth, or compactness.
• Optical parametric oscillators (OPOs) offer a versatile platform for generating tunable mid-IR light.

Purpose of the Study:

• To demonstrate a compact and efficient source of broadband, high-power, cw, mid-IR radiation.
• To investigate the performance of a singly resonant optical parametric oscillator (SRO) pumped by a Yb fiber laser.
• To achieve broad spectral coverage in the mid-IR region.

Main Methods:

• Utilizing a singly resonant optical parametric oscillator (SRO) configuration.
• Employing a wide-bandwidth continuous-wave (cw) Ytterbium (Yb) fiber laser operating at 1060 nm as the pump source.
• Exploiting the extended phase-matching bandwidth in a 50 mm crystal of periodically poled lithium niobate (MgO:PPLN) within a ring SRO cavity.

Main Results:

• Achieved 5.3 W of broadband idler output with >80% pump depletion for 25.5 W of pump power.
• Transferred a pump bandwidth of 73.9 cm⁻¹ to an idler spectrum centered at 3454 nm, covering an equal bandwidth.
• Generated 11.2 W of total power with 44% extraction efficiency by coupling out the signal beam, demonstrating >73% pump depletion.

Conclusions:

• The developed SRO system represents a compact and viable source for broadband, high-power, cw, mid-IR radiation.
• The use of MgO:PPLN and a ring cavity effectively broadens the idler spectrum.
• The demonstrated performance highlights the potential of this laser system for various spectroscopic and sensing applications.