Optofluidic laser array based on stable high-Q Fabry–Pérot microcavities

Abstract

We report the development of an optofluidic laser array fabricated on a chip using stable plano-concave Fabry-Pérot (FP) microcavities, which are far less susceptible to optical misalignment during device assembly than commonly used plano-plano FP microcavities. The concave mirrors in our FP microcavities were created by first generating an array of microwells of a few micrometers in depth and a few tens of micrometers in diameter on a fused silica chip using a CO2 laser, followed by coating of distributed Bragg reflection (DBR) layers. The planoconcave FP microcavity had a Q-factor of 5.6×105 and finesse of 4×103, over 100 times higher than those for the FP microcavities in existing optofluidic lasers. 1 mM R6G dye in ethanol was used to test the plano-concave FP microcavities, showing an ultralow lasing threshold of only 90 nJ/mm2, over 10 times lower than that in the corresponding unstable plano-plano FP microcavities formed by the same DBR coatings on the same chip. Simultaneous laser emission from the optofluidic laser array on the chip and single-mode lasing operation were also demonstrated. Our work will lead to the development of optofluidic laser based biochemical sensors and novel on-chip photonic devices with extremely low lasing thresholds (nJ/mm2) and mode volumes (fL).

Versatile tissue lasers based on high-Q Fabry–Pérot microcavities

“…S1) and tested with the same FITC stained muscle tissue. The Q-factor of those p-c FP cavities exceeded 10 5 , according to our previous work 38 . As shown in Fig.…”

“…The Q-factor for the p-p and p-c FP cavity was on the order of 10 4 and 10 5 , respectively, at a cavity length of 30 μm (in the absence of tissues). Details of the fabrication and characterization of the p-p and p-c FP cavities are described in the reference 38 .…”

Lasing in blood

“…As discussed previously, ICG lasing may help improve differentiation and identification of vital structures in tissues. To implement, a high-Q Fabry–Perot cavity (the Q -factor is as high as 6 × 10 5 [46], close to that of the OFRR used in the current work) can be employed for in vitro biological imaging and spectroscopy due to its planar format. (2) In vivo characterization and differentiation of tissues.…”

On-chip High-finesse Fabry-Perot Microcavities for Optical Sensing and Quantum Information

“…Conversely, Coles et al [58] were able to achieve CW operation without pumping, owing to the diffusion of organic molecules into and out of the small VM gain region of their spherical-mirror FPC. In parallel with these efforts, a group in China [22,60] has recently reported low-threshold dye lasers based on high-finesse (F ~10 3 ) spherical-mirror FPCs fabricated using a wafer-bonding approach. The field of spherical-mirror, open-access microcavity lasers is in its infancy, and promises to yield many exciting results in the coming years.…”