Silicon based photonic crystal coupled to an optical cavity for highly sensitive biodetection

Since its discovery by Sir John Frederick William Herschel in 1845, fluorescence detection technology has developed extensively to be used in disease diagnosis, DNA sequencing, cellular imaging, flow cytometry, forensics, and monitoring processes in biological systems. In order to achieve better sensitivity and higher signal-to-noise ratio (SNR), metal-enhancement fluorescence and nano-engineered surfaces were used to augment the excitation of fluorophores and provide directionality to the emitted light for improved collection. Photonic crystals (PCs), which are composed of periodically refractive index modulated nano-structures, have proven to be a great surface for improving the emission from surface-bound fluorophores. When the resonant guided mode condition is reached, PCs provide fluorescence enhancement mainly through two mechanisms: enhanced excitation and enhanced extraction. This thesis addresses the design, fabrication, and characterization of a silicon based PC coupled to an optical cavity. Compared to an ordinary PC without coupled optical cavity, the new PC can further increase fluorescent output via stronger evanescent field. A fluorescent dye tagged protein detection experiment was conducted on the new PC showing that it provides 10x SNR, opening the door for detection of biomarkers in sub-pg/ml range.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Tang, Tiantian

• Photonic crystal enhanced fluorescence

Statement dc:rights

• Copyright 2015 Tiantian Tang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/78797

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/78797