Precise intracavity phase interferometry in an optical parametric oscillator with two pulses per cavity round trip

Area of Science:

• Optics and Photonics
• Nonlinear Optics
• Interferometry

Background:

• Precise measurement of optical phase shifts is crucial for characterizing nonlinear optical materials.
• Traditional methods like the z-scan technique have limitations in sensitivity and accuracy for certain measurements.
• Femtometer-level precision in cavity length changes requires advanced interferometric approaches.

Purpose of the Study:

• To demonstrate a novel intracavity phase interferometry technique for measuring small phase shifts.
• To apply this technique for accurate determination of the nonlinear index of refraction.
• To compare the performance of this method against the established z-scan technique.

Main Methods:

• Development and implementation of an intracavity phase interferometry setup.
• Utilizing a synchronously pumped optical parametric oscillator as the light source.
• Measurement of phase shifts as low as 10⁻⁷ radians.

Main Results:

• Successful measurement of phase shifts in the order of 10⁻⁷ radians.
• Demonstration of femtometer-scale precision in detecting cavity length variations.
• Achieved higher accuracy and sensitivity in nonlinear refractive index measurement of lithium niobate compared to the z-scan method.

Conclusions:

• Intracavity phase interferometry is a highly sensitive and accurate method for optical measurements.
• The technique shows significant advantages over traditional methods for nonlinear optical characterization.
• This approach enables precise measurements of material properties at the femtometer scale.