Refractive index measurement deflectometry for measuring gradient refractive index lens

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Gradient refractive index (GRIN) lenses are crucial optical components.
• Accurate measurement of their refractive index distribution is essential for performance optimization.

Purpose of the Study:

• To propose and validate a novel deflectometry-based method for measuring the refractive index distribution of radial GRIN lenses.
• To establish a relationship between refractive index and light ray direction in non-uniform media.

Main Methods:

• Derivation of light propagation equations in non-uniform media.
• Application of deflectometry principles to measure light deflection angles.
• Assumption of central refraction for refractive index determination.
• Numerical simulations and experimental validation.

Main Results:

• The proposed refractive index measurement deflectometry (RIMD) method accurately determines radial GRIN lens refractive index distributions.
• Numerical simulations verified the method's correctness and accuracy.
• Experimental results showed good consistency with nominal parameters, with measurement errors within 10⁻³.
• Analysis of calibration errors and lens surface shape effects on measurement accuracy was performed.

Conclusions:

• The developed deflectometry method offers a rapid and convenient way to acquire full-field refractive index information for GRIN lenses.
• This technique shows significant potential for advancing lens manufacturing and quality control processes.