Decreased oscillation threshold of a continuous-wave OPO using a semiconductor gain mirror

Area of Science:

• Nonlinear optics
• Semiconductor laser technology

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Traditional OPOs often require high pump powers or complex cavity designs.
• Semiconductor gain elements offer potential for compact and efficient light sources.

Purpose of the Study:

• To develop a singly resonant optical parametric oscillator (SRO) utilizing a semiconductor gain mirror.
• To investigate the impact of the semiconductor gain mirror on oscillation threshold and performance.
• To characterize the tuning range and output stability of the developed OPO.

Main Methods:

• Construction of a singly resonant OPO with a semiconductor gain mirror replacing a conventional mirror.
• Characterization of the oscillation threshold by comparing with an identical system using conventional mirrors.
• Measurement of the idler beam tuning range by varying the pump laser wavelength.
• Assessment of single-mode output power and tunability through the addition of intra-cavity optical components.

Main Results:

• The semiconductor gain mirror significantly reduced the oscillation threshold compared to conventional mirrors.
• A wide idler beam tuning range of 3.6 to 4.7 µm was achieved solely by adjusting the pump laser wavelength.
• Limited single-mode output power was observed but could be continuously scanned over at least 220 GHz with added optical components for enhanced stability.

Conclusions:

• A semiconductor gain mirror is an effective method for decreasing the oscillation threshold in singly resonant OPOs.
• The developed OPO demonstrates a broad tuning capability and potential for stable, tunable single-mode operation.
• This approach offers a promising pathway for developing more efficient and compact tunable light sources.