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

Photonic crystal enhanced fluorescence

Tang, Tiantian

关键词: Photonic crystal enhanced fluorescence;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/78797/TANG-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

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.