Coupling Variation Induced Ultrasensitive Label-Free Biosensing by Using Single Mode Coupled Microcavity Laser
ABSTRACT A novel label-free optical biosensing scheme by using a single mode coupled microcavity laser is experimentally realized. We demonstrate that a slight change of the coupling coefficient due to the existence of biosamples leads to sensitive single mode laser hopping to a new frequency that is several nm away from the original mode wavelength. By monitoring the emergence of the hopped laser mode intensity, the lowest detectable concentration of bovine serum albumin (BSA) of approximately 80 pg/mL was obtained, which is comparable to the detection limit of a passive microcavity sensor with Q > 10(7), but with a much simplified experimental setup. With the mode hopping and mode shift combined, the single frequency coupled cavity laser provides a detection range from pg/mL (limit of mode hopping) to microg/mL (limit of mode shift). Our results show the possibility of using a coupled optical microcavity to achieve ultrasensitive optical sensing.
[Show abstract] [Hide abstract]
ABSTRACT: We report the design, fabrication, and demonstration of a chemical sensor-based on the spectral shift of organic microcavity lasers. The shape of the cavity contour is used as a parameter and is optimized to improve the sensitivity. Analytical and numerical predictions are in good agreement with experiments performed in a microfluidic environment, showing sensitivities of up to 100 nm per refractive index unit for stadium-shaped microlasers on pedestal. Selective sensing of Hg2+ at a concentration down to 200 ppb is then demonstrated with cavities functionalized by ligands that are known to bind mercuric cations.Applied Physics B 10/2014; 117(1):501-508. DOI:10.1007/s00340-014-5861-7 · 1.63 Impact Factor
03/2014; 2(3). DOI:10.1002/adom.201300433
05/2013; 1(5). DOI:10.1002/adom.201200065