Wavelength tunable, single-longitudinal-mode optical parametric oscillator with a transversally chirped volume Bragg...

Area of Science:

• Nonlinear Optics
• Laser Physics
• Materials Science

Background:

• Optical parametric oscillators (OPOs) are crucial for generating tunable laser light.
• Achieving single-longitudinal-mode (SLM) operation in OPOs is challenging due to broad gain bandwidths.

Purpose of the Study:

• To demonstrate single-longitudinal-mode (SLM) operation in a low-threshold optical parametric oscillator (OPO).
• To achieve tunable output with a 17 nm bandwidth near 2 µm.
• To investigate spectral selection mechanisms in MgO:PPLN based OPOs.

Main Methods:

• Utilized a magnesium-oxide-doped periodically poled lithium niobate (MgO:PPLN) crystal in a Type 0 quasi-phase-matching configuration.
• Employed a 1.064 µm single-longitudinal-mode (SLM) laser as the pump source.
• Implemented spectral selection using a volume Bragg reflector and Vernier filtering within nested signal and idler cavities.

Main Results:

• Achieved low-threshold single-longitudinal-mode (SLM) operation of the optical parametric oscillator (OPO).
• Demonstrated a tunable output with a 17 nm bandwidth centered near 2 µm.
• Verified effective spectral selection despite the broad acceptance bandwidth of MgO:PPLN near degeneracy.

Conclusions:

• The combination of a volume Bragg reflector and Vernier filtering successfully enables SLM operation in a MgO:PPLN OPO.
• Transverse chirp in the Bragg reflector's grating period is key to achieving broad tunability.
• This work presents a viable method for generating narrow-linewidth tunable light sources.