Biocompatible Polymer and Protein Microspheres with Inverse Photonic Glass Structure for Random Micro‐Biolasers

Abstract

The miniaturization of random lasers to the micrometer scale is challenging but fundamental for the integration of lasers with photonic integrated circuits and biological tissues. Herein, it is demonstrated that random lasers with a diameter from 30 to 160 μm can be achieved by using a simple emulsion process and selective chemical etching. These tiny random laser sources are made of either dye‐doped polyvinyl alcohol (PVA) or bovine serum albumin (BSA) and they are in the form of microporous spheres with monodisperse pores of 1.28 μm in diameter. Clear lasing action is observed when the microporous spheres are optically excited with powers larger than the lasing threshold, which is 154 μJ mm−2 for a 75 μm diameter PVA microporous sphere. The lasing wavelength redshifts 10 nm when the PVA microsphere diameter increases from 34 to 160 μm. For BSA microspheres, the lasing threshold is around 55 μJ mm−2 for a 70 μm diameter sphere and 104 μJ mm−2 for a 35 μm diameter sphere. The simple fabrication process reported allows for detail studies of morphology and size, important for fundamental studies of light–matter interaction in complex media, and applications in photonic integrated circuits, photonic barcoding, and optical biosensing.

Random lasers from the natural inverse photonic glass structure of Artemia eggshells

“…A possible interpretation for this effect is that the larger the laser size results in more lasing modes, thus, leading to a broader spectral width. Similar observations are also observed on random microlasers based protein microspheres with the inverse photonic glass structure [26].…”

Properties and Applications of Random Lasers as Emerging Light Sources and Optical Sensors: A Review

“…For instance, Ignesti et al [ 111 ] reported a maximum redshift of around 50 nm when increasing concentrations of intralipid in a dye solution. Other approaches, such as using larger microspheres diameters [ 116 ] and increasing the laser cavity lengths [ 117 ], also facilitate the peak wavelength redshift.…”

Droplet Lasers for Smart Photonic Labels

“…SiO 2 -doped droplets instead do not show The observed behavior points out that the dielectric particles included in the droplets, besides gradually modifying the droplet's internal refractive index, may assemble into aggregates that act as sites suitable for the light confinement. 45,46 More specifically, such a system made up of a gain medium enclosing disordered ensembles of particles is defined as RL. 47 The aggregates behave as centers for the multiple scattering of light that above a certain pump threshold results in stimulated emission.…”