Table 3.

Commonly used Optical Microcavities of Biolasers for biological applications

Optical Microcavities	Description	Applications
Fabry-Pérot (FP) cavity	Constructed using a pair of parallel plane mirrors, sandwiching the gain medium between them. This allows bulk interaction between light and the gain medium, enhancing the direct interaction of light with matter.	Optofluidic laser-based detection 66-69 Single Cell based intracellular sensing, cytometry and imaging 58,62,70,71,65 Tissue lasers 72,73 Scanning “laser-emission-based microscope” (LEM) for detection of specific intracellular biomarkers 74,75 Laser pArticle Stimulated Emission (LASE) microscopy 76
Whispering Gallery Mode (WGM) cavity	The WGM cavity relies on the total internal reflection at the curved boundary where the light rays are trapped inside the cavity circulating along the curved boundary. WGM microcavities have been constructed in various forms starting from circular shaped capillaries, microdisks, microdroplets, microspheres, solid cylinders, ring-shaped waveguides to rectangular shaped rods.	Biosensing, Cell tagging and tracking 45,77-82 Studying Protein-protein interactions and protein-drug interactions 83 Chlorophyll based optofluidic laser 84 Lasing in human blood 85 Implantable tissue lasers 86 Biomolecule detection system 87
Distributed Feedback Laser (DFB) cavity	DFB microcavity consist of periodical structures to provide optical feedback with the gain material.	Lasing 52 Membrane lasers 88 Biosensing 89
Random Laser (RL) cavity	A RL does not have a fixed optical cavity and the optical feedback is provided by multireflections from scattering particle dispersed in the lasing active material.	Tissue mapping 90-92 Label-free biofluidic lasers 93 Tissue Laser 94,95 Lasing 96,97 Biosensing 49,98 Opto-chemical therapies 99