NOVEL OPTICAL DEVICES FOR BIOMEDICAL IMAGING AND SPECTROSCOPY
Open Access
- Author:
- Zhang, Chenji
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- November 05, 2017
- Committee Members:
- Zhiwen Liu, Dissertation Advisor/Co-Advisor
Zhiwen Liu, Committee Chair/Co-Chair
Iam-Choon Khoo, Committee Member
Chris Giebink, Committee Member
Siyang Zheng, Outside Member - Keywords:
- Optics
Optical spectroscopy
Biomedical
Ultrafast Optics
Nonlinear Optics
Optical fiber
Optical imaging
Bio-sensing - Abstract:
- With the growing demand for better medical care worldwide, biomedical imaging and spectroscopy which provide critical information for disease diagnosis and personal health condition have become a focal point. In order to output high quality imaging and spectroscopy results, which is critical for diagnosis accuracy, optical devices have been extensively explored. In this dissertation, I present several novel optical devices for biomedical imaging and spectroscopy. They are all capable of promoting the performance of existing imaging and spectroscopy applications or enabling new applications. In Chapter two, I present a laser based light source which is ultrafast, multi-line, dual polarization, broadly tunable, and power scalable. This light source could be an ideal source for nonlinear optical imaging. We combine soliton self-frequency shift and pulse division method together to achieve these features. Specifically, power scalable is achieved through pulse division and recombination, which provides a general solution for conventional soliton self-frequency shift source whose pulse energy is limited. Also, benefited from the pulse division, divided pulses can be shifted individually, which enables multi-wavelength and dual polarization capability. Simultaneous dual-polarization second-harmonic generation imaging is demonstrated based on these features. In Chapter three, I present a biodegradable step-index optical fiber, which is suitable for light delivery under in vivo condition. The fiber has desirable mechanical and biological properties which are superior to traditional silica optical fiber. This is attributed to the programmable citrate-based material platform we use to fabricate the fiber. The fiber has a 0.4dB/cm loss, with a 1/e length longer than 10cm. By using this fiber, successful light delivery in tissue as well as fluorescence excitation and collection are accomplished, which prove the fiber’s usefulness for in vivo applications. Further, successful image delivery verifies the fiber’s ability for image transmission, which can potentially enable endoscopy applications. In Chapter four, I demonstrate two smartphone based detection devices, suitable for spectroscopy applications. Both of them benefit from the smartphone, which is ideal for point-of-care applications. Specifically, we developed a G-Fresnel smartphone based spectrometer. Successful protein concentration measurement using Bradford reagents demonstrates its ability for general spectroscopy applications. In additional to the smartphone spectrometer, we also developed a smartphone chloridometer based on a citrate chloride sensor. Through clinical verification, the device shows high accuracy and broad measurement range, which can potential serve as a device for cystic fibrosis diagnosis.