Precise measurement of the Kerr coefficient using phase-sensitive pump-probe hyperspectral imaging

Area of Science:

• Nonlinear optics
• Optical spectroscopy
• Materials characterization

Background:

• Accurate measurement of the optical Kerr coefficient (n2) is crucial for nonlinear optical applications.
• Existing techniques like Z-scan have limitations in precision and absolute measurements.
• Understanding nonlinear optical responses requires precise characterization of material properties.

Purpose of the Study:

• To develop and demonstrate a phase-sensitive pump-probe hyperspectral imaging technique for absolute two-beam n2 measurements.
• To benchmark the new technique against the widely used Z-scan method.
• To analyze and detail uncertainty contributions for improved precision.

Main Methods:

• Utilizing phase-sensitive pump-probe hyperspectral imaging with raster scanning of the pump beam across the probe beam.
• Acquiring complex-valued hyperspectral images to capture the pump-induced nonlinear response.
• Analyzing spectral response to extract information about the temporal irradiance profile.

Main Results:

• Successfully measured the n2 of a fused silica sample near 1 μm wavelength.
• Demonstrated consistency between hyperspectral imaging and Z-scan measurements when considering the two-beam grating effect.
• Detailed analysis of uncertainty contributions for the technique.

Conclusions:

• Phase-sensitive pump-probe hyperspectral imaging provides a precise method for absolute n2 determination.
• The technique offers advantages over single-beam methods, especially when Raman contributions are considered.
• Future improvements in precision are anticipated for this advanced optical measurement technique.