Third-order optical susceptibility of glasses determined by third harmonic generation

Area of Science:

• Nonlinear optics
• Materials science

Background:

• Accurate measurement of nonlinear optical properties is crucial for advanced optical applications.
• BK-7 glass and fused silica are common optical materials with varying densities.

Purpose of the Study:

• To measure the third-order nonlinear optical susceptibilities of BK-7 glass and fused silica.
• To compare these properties relative to alpha-quartz using nonphasematched optical third harmonic generation (THG).
• To investigate the relationship between linear optical properties, density, and a generalized Miller delta parameter.

Main Methods:

• Nonphasematched optical third harmonic generation (THG) was employed.
• Two fringe analysis methods were used: sequential measurements of individual wedges and simultaneous placement of sample and standard wedges.
• Linear optical properties were correlated with material density.

Main Results:

• Third-order nonlinear optical susceptibilities for BK-7 glass and fused silica were determined relative to alpha-quartz.
• Linear optical properties were found to scale with material density.
• A generalized Miller delta parameter, incorporating density variations, provided a superior predictive model.

Conclusions:

• The study successfully quantified nonlinear optical properties of BK-7 glass and fused silica.
• Material density is a key factor influencing linear optical properties.
• The generalized Miller delta parameter offers improved accuracy in predicting nonlinear optical behavior by accounting for density.