Tunable narrowband optical parametric oscillator using a transversely chirped Bragg grating.

Area of Science:

• Nonlinear Optics
• Laser Physics
• Spectroscopy

Background:

• Optical Parametric Oscillators (OPOs) are crucial for generating tunable laser light.
• Existing tuning methods for nanosecond OPOs can be complex or limited in range.
• Precise wavelength control is essential for various spectroscopic and photonic applications.

Purpose of the Study:

• To demonstrate a novel and widely applicable technique for locking and tuning nanosecond optical parametric oscillators (OPOs).
• To achieve broad wavelength tunability in the near-infrared region using a simple mechanical method.
• To develop a robust method for generating narrowband tunable light sources with high background suppression.

Main Methods:

• Utilized a transversely chirped volume Bragg grating for wavelength selection and tuning.
• Employed a periodically poled KTiOPO(4) nonlinear crystal within the OPO cavity.
• Pumped the OPO at 532 nm with nanosecond pulses and analyzed the output signal characteristics.

Main Results:

• Achieved continuous wavelength tuning of the OPO signal from 1011 to 1023 nm (3.5 THz) by translating the grating.
• Generated signal pulses with energies up to 0.37 mJ.
• Obtained a narrow signal bandwidth of 0.50 nm with broadband background suppression exceeding 30 dB.

Conclusions:

• The demonstrated chirped volume Bragg grating technique offers an effective method for tuning nanosecond OPOs.
• This approach provides a versatile platform for constructing narrowband tunable light sources.
• The technique's simplicity and wide applicability make it suitable for various laser-based applications.