MSE PhD proposal- Gyu Hyon (Eric) Lee

Date: Monday, December 7th 2015 

Time: 10:30 AM

Location: MRDC 3515 

Title: Fabrication and Application of Photonic Crystal and Nano-Photonic Structures in Dynamic Sensing and Light Extraction

Committee:
Prof. Christopher Summers, Advisor, MSE 
Prof. Zhitao Kang, Advisor, MSE/GTRI 
Prof. Naresh Thadhani, MSE 
Prof. Meilin Liu, MSE 
Dr. Brent Wagner, GTRI 

Abstract

Photonic crystals (PCs) and nano-photonic structures such as optical microcavities (OMCs) have been investigated widely for many different applications. PCs and OMCs’ well-defined physical dependence to its optical characteristics had been applied in many different sensor applications such as mechanical, gas, chemical, and bio photonic-sensors. Also, due to PC’s inherent ability to waveguide specific frequency of lights, PCs can be utilized to improve the efficiency of devices such as LEDs. This study is designed to further investigate potential applications of such nano-photonic structures employing these characteristics.        

One of the application of PCs and OMCs investigated in this study is to use them as dynamic loading (shock) sensors. The behavior of a system with meso-scale variation under shock is significantly different from the continuum behavior but the knowledge is deficient due to the lack of such sensors that are capable of providing distinguishable information with a spatial resolution in such time frame. These photonic structures have spectral properties directly related to their dimensions and have high potentials as the dynamic loading sensor. The change in structure due to shock can almost instantaneously be reflected as the observable change in their optical properties. In this study, we will investigate various designs of nano-photonic structures and photonic crystal structures that can potentially be used as a precise shock loading sensor with a spatial resolution.

Another application of PCs investigated in this study is to use it as a light output coupler of scintillators to photomultiplier (PMTs) tubes. Nanocomposite glass ceramic scintillators have many advantages such as large scalability, good thermal, chemical and mechanical stability, and economical manufacturing and material cost. However, the light output is lacking. Light output of the scintillator can be improved by utilizing PCs ability to waveguide specific frequency of lights. When the PC lattice structures are employed on the surface of the nanocomposite scintillators, propagation of emitted light would be directionally controlled, and internal reflections would be minimized. These scintillators would demonstrate a significant increase in light collection efficiency as emitted light will be perpendicularly guided to the PMTs. Furthermore, we will systematically investigate various factors to improve the light yield of the transparent nanocomposite scintillator itself such as glass compositions, volume fractions of active nanocrystals to glass matrix and choice of nanocrystals. A significant improvement in light output of the transparent glass ceramic scintillator is anticipated from systematical investigations in conjunction with PC lattice after the successful completion of this study.