Abstract

Freeform optics enables enhanced system performance and packaging due to the high degrees of design freedom they provide, but characterizing these optics remains challenging. Phase measurement of an optical wave is essential in the metrology of optical components, adaptive optics, and laser beam quality assessment. The Shack-Hartman Wavefront Sensors are limited by their dynamic range and resolution due to lenslet operation. Interferometric-method-based adaptive nulling requires high-performance wavefront sensor, and coordinate-scanning-based measurements are time consuming. We investigate and develop an Optical Differentiation Wavefront Sensor (ODWS) based on binary pixelated filter that enables high dynamic range, high resolution freeform metrology. Analysis of experimental results and comparison with commercial metrology show that phase plates with different magnitude of wavefront slopes can be accurately characterized. We created an ODWS design that reduced the footprint by five times compared to typical 4f arrangement for the same effective focal length. We further investigated the system alignment tolerance. We report on the theoretical and experimental demonstration of an ODWS based on binary pixelated linear and nonlinear amplitude filtering in the far-field. We trained and tested a convolutional neural network that reconstructs spatial phase map from nonlinear filter based ODWS images where an analytic solution is not available. It shows accurate retrieval (~0.05λ root mean square error) over different magnitude of wavefronts and on random shaped wavefronts. This work paves the way for realizing simultaneous sensitive, high dynamic range and high-resolution wavefront sensing.

Publication Date

2024

Document Type

Dissertation

Student Type

Graduate

Degree Name

Imaging Science (Ph.D.)

Department, Program, or Center

Chester F. Carlson Center for Imaging Science

College

College of Science

Advisor

Jie Qiao

Advisor/Committee Member

Grover Swartzlander

Advisor/Committee Member

Christopher Kannan

Campus

RIT – Main Campus

Download

Share

COinS