Rolled-up optical microcavities with subwavelength wall thicknesses for enhanced liquid sensing applications.
Microtubular optical microcavities from rolled-up ring resonators with subwavelength wall thicknesses have been fabricated by releasing prestressed SiO/SiO(2) bilayer nanomembranes from photoresist sacrificial layers. Whispering gallery modes are observed in the photoluminescence spectra from the rolled-up nanomembranes, and their spectral peak positions shift significantly when measurements are carried out in different surrounding liquids, thus indicating excellent sensing functionality of these optofluidic microcavities. Analytical calculations as well as finite-difference time-domain simulations are performed to investigate the light confinement in the optical microcavities numerically and to describe the experimental mode shifts very well. A maximum sensitivity of 425 nm/refractive index unit is achieved for the microtube ring resonators, which is caused by the pronounced propagation of the evanescent field in the surrounding media due to the subwavelength wall thickness design of the microcavity. Our optofluidic sensors show high potential for lab-on-a-chip applications, such as real-time bioanalytic systems.
Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, D-01069 Dresden, Germany. gaoshan.huang@gmail.com
Gaoshan
G
Huang
Vladimir A
VA
Bolaños Quiñones
Fei
F
Ding
Suwit
S
Kiravittaya
Yongfeng
Y
Mei
Oliver G
OG
Schmidt
D003460:Crystallization / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008567:Membranes, Artificial; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D055096:Optical Devices; D010316:Particle Size; D012031:Refractometry / Q000295:instrumentation; D012996:Solutions / Q000032:analysis* / Q000737:chemistry*; D014159:Transducers
D008567:Membranes, Artificial; D012996:Solutions