Single-mode, tunable output from a midwave-infrared-seeded optical parametric oscillator system

Area of Science:

• Optics and Photonics
• Laser Physics
• Infrared Technology

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser radiation.
• Achieving single-frequency, pulsed output in the midwave infrared (MWIR) presents significant challenges.
• Existing systems may lack the narrow linewidth required for specific applications.

Purpose of the Study:

• To develop a coupled master-slave oscillator optical parametric oscillator (OPO) system.
• To generate single-frequency, pulsed radiation in the midwave infrared (MWIR) spectrum.
• To achieve a narrow linewidth suitable for coherent differential absorption lidar.

Main Methods:

• A direct-diode-pumped master OPO generated tunable MWIR continuous-wave (cw) radiation.
• This MWIR cw radiation seeded a higher-peak-power pulsed slave OPO.
• The slave OPO was seeded at the MWIR idler to enforce single longitudinal mode operation.

Main Results:

• The master OPO produced narrow-band (<6-MHz) tunable MWIR cw radiation.
• The seeded slave OPO achieved single longitudinal mode oscillation despite a multi-longitudinal-mode pump laser.
• The pulsed output linewidth was measured to be <220 MHz (instrument limited).

Conclusions:

• The coupled master-slave OPO system successfully generates single-frequency, pulsed MWIR radiation.
• The narrow linewidth of the pulsed output makes it suitable for coherent differential absorption lidar.
• This technology advances capabilities in infrared spectroscopy and remote sensing.