Graduation Year


Document Type




Degree Granting Department


Major Professor

Myung K. Kim, Ph.D.


Interferometry, Phase contrast microscopy, Interference microscopy, Phase shifting


The results presented here are divided into three main categories based on the source of illumination; light emitting diodes, laser diodes and a ring dye laser. Results for both two-wavelength optical unwrapping and three-wavelength optical unwrapping techniques are demonstrated. The interferographic images using broadband sources such as light emitting diodes are significantly less affected by coherent noise compared to images obtained using lasers. Our results show that the three wavelength optical phase unwrapping can also be effectively applied to unwrap phase images obtained using coherent light sources such as lasers and laser diodes, without amplifying phase noise in the final phase image. We have successfully shown that our multi-wavelength phase-shifting technique extends the range free of 2p ambiguities in the phase map without using conventional computation intensive phase unwrapping methods.

This phase imaging technique can be used to measure physical thickness or height of both biological and other microscopic samples, with nanometer axial resolution. An added advantage of the multi-wavelength optical phase unwrapping technique is that the beat wavelength can be tailored to match height variations of specific samples.