Miniature objective lens design for multiphoton microscopy
department or school: Applied Science, Faculty of
department or school: Electrical and Computer Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Brandt, Christoph Tobias
issued: 2022-10-20T20:12:33Z
issued: 2022
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Multiphoton microscopy is a promising imaging technique capable of optical sectioning to acquire images from below the surface of tissue. A miniature objective with depth-scanning capability is needed for clinically adaptation. Imaging performance is dependent upon the ability to focus pulsed laser light. State-of-the-art endoscopes have a depth-scanning capability of ~200 μm and suffer from a significant decrease in resolution at the limit of their depth-scanning range. Zemax software is used to evaluate aspherical lenses for use as objectives, to evaluate the effect of scanning optics, and to design a custom water-dipping objective. Simulations show that the custom objective is capable of achieving diffraction-limited focusing for depths from 0 μm to 1400 μm in water by minimizing spherical aberration. A shape memory alloy actuator is used by the objective for depth-scanning across a 440 μm range, which is experimentally demonstrated by imaging fluorescent beads across the entire range and is more than double the range capability of MPM endoscopes in literature. Resolution measured ~0.7 μm laterally and ~10 μm axially and remained consistent across the entire depth-scanning range. This is a significant improvement to both our lab’s imaging ability and to the depth-scanning abilities of endoscopes presented in literature. Resolution is improved by the addition of corrective optics that reduces axial chromatic aberration. The effect of chromatic aberration on the focusing ability of the custom objective is investigated via simulation using Zemax. Simulations show that the 3 dB wavelengths of the laser’s 80 fs pulses focus at a different depth than the central wavelength and also that marginal rays and on-axis rays arrive at the focal point at different times. By adding CO to reduce chromatic aberration, both of these differences are significantly reduced, which improves the signal to noise ratio. An equation to calculate the difference in arrival time is derived, wh…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/82938
note: MINIATURE OBJECTIVE LENS DESIGN FOR MULTIPHOTON MICROSCOPY by CHRISTOPH TOBIAS BRANDT BASc., The University of British Columbia, 2008 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Electrical and Computer Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) October 2022 © Christoph Tobias Brandt, 2022 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Miniature Objective Lens Design for Multiphoton Microcopy submitted by Christoph Tobias Brandt in partial fulfilment of the requirements for the degree of Master of Applied Science in Electrical and Computer Engineering Examining Committee: Shuo Tang, Professor, Electrical and Computer Engineering, UBC Supervisor Lukas Chrostowski, Professor, Electrical and Computer Engineering, UBC Supervisory Committee Member Sudip Shekhar, Associate Professor, Electrical and Computer Engineering, UBC Supervisory Committee Member iii Abstract Multiphoton microscopy is a promising imaging technique capable of optical sectioning to acquire images from below the surface of tissue. A miniature objective with depth-scanning capability is needed for clinically adaptation. Imaging performance is dependent upon the ability to focus pulsed laser light. State-of-the-art endoscopes have a depth-scanning capability of ~200 μm and suffer from a significant decrease in resolution at the limit of their depth-scanning range. Zemax software is used to evaluate aspherical lenses for use as objectives, to evaluate the effect of scanning optics, and to design a custom water-dipping objective. Simulations show that the custom objective is capable of achieving diffraction-limited focusing for depths from 0 μm to 1400 μm in water by minimizing spherical aberration. A shape memory alloy actuator is used by the objective for depth-sc…
has type: Thesis/Dissertation
date issued: 2022-11
is shown at: 10.14288/1.0421394
language: eng
degree discipline: Electrical and Computer Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Tang, Shuo
type: Text
identifier URI: http://hdl.handle.net/2429/82938