Title

Nonlinear Microscopy Based on Femtosecond Fiber Laser

Author

Xiaowei Ge

Date of Award

1-1-2019

Degree Name

M.S. in Electro-Optics

Department

Department of Electro-Optics

Advisor/Chair

Advisor: Andy Chong

Abstract

Nonlinear microscopy is an indispensable tool for biopsy and other kinds of sample detection, which can protect the sample from dye and redundant cutting. The penetration depth allows the detection of specific goals hidden under other coverage. If the sample is low melting point material, by using nanolithography to coat the sample with gold nanoparticles, it is feasible to do micro-dimension fabrication. We are going to present how to establish nonlinear microscopy theoretically and experimentally.The nonlinear microscopy consists of three parts, microscope, light source and the optical beam path. The microscope setup is comprised of objective, the dichroic mirror, sample carrier stage and the detector. This microscope is a scanning laser microscope (SLM). We are using linear scanning, scanning stage (LSSS) method and the carrier stage is a 2D motorized assembled stage. The nonlinear imaging principles are discussed and categorized. We choose potassium dihydrogen phosphate (KDP) as the sample to testify the feasibility of the nonlinear microscopy. Second harmonic generation (SHG) is the nonlinear signal used to reconstruct the shape of the sample.For the light source, we are using all-normal-dispersion (ANDi) femtosecond ber laser, whose pulse is around 100 femtosecond with 20 kW peak power. The self-started, compact femtosecond ber laser provides stable and high peak power pulses. A short pulse with 10 kW peak power is guided by the optical components onto the sample and generates second harmonic signal.

Keywords

Electrical Engineering, Optics, Nonlinear microscopy, ultrafast fiber laser, stage scanning method, particle identification

Rights Statement

Copyright 2019, author

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