Chromaticity-tunable white random lasing based on a microfluidic channel

Abstract

The color and/or chromaticity controllability of random lasing is a key factor to promote practical applications of random lasers as high luminance sources for speckle-free imaging. Here, white coherent random lasing with tunable chromaticity is obtained by using broadband enhancement Au-Ag nanowires as scatterers and the resonance energy transfer process between different dyes in the capillary microfluidic channel. Red, green and blue random lasers are separately fabricated with low thresholds, benefiting from the plasmonic resonance of the nanogaps and/or nanotips with random distribution and sizes within Au-Ag nanowires and positive optical feedback provided by the capillary wall. A white random laser system is then designed through reorganizing the three random lasers. And, the chromaticity of the white random laser is flexibly tunable by adjusting pump power density. In addition, the white random laser has anisotropic spectra due to the coupling role between the lasers. This characteristic is then utilized to obtain different random lasing with different chromaticity over a broad visible range. The results may provide a basis for applying random laser in the field of high brightness illumination, biomedical imaging, and sensors.

Fiber Optofluidic Microlasers: Structures, Characteristics, and Applications

“…[ 193 ] Notably, random laser can generate angle‐free and laser‐level radiation, which may be more useful than traditional laser in headlights and spotlights. [ 194 ] As shown in Figure 11d, light‐emitting polymers doped with Ag nanoparticles and PVA spacers were alternately decorated on the fiber endface, with a thickness of about 3.6 µm, by dip‐coating method to form a plasmonic enhanced RGB random laser. [ 195 ]…”

Recent progress and prospects of random lasers using advanced materials

“…Such unique configuration leads to lasers with low spatial coherence. Therefore, it renders RLs as an attractive platform for many applications such as cancer diagnostic 10,11 , Photonic barcodes 12 , a random spectrometer on a chip 13 , speckle-free bio-imaging 14 , speckle-free pulsed imaging technique 15 , sensing 16,17 , optical batteries 18 and optomicrofluidics 19,20,21 . The first type of RLs were dye-based colloidal systems 4,22 and then on many other systems like photonic crystals [23][24] , semiconductors 25,26,27 , quantum dots (QDs) 28,29 , polymeric matrices [30][31] , biological tissues 32 , rare-earth-doped nanopowders 33 , cold atoms 34 , etc.…”

Programmable Rainbow-Colored Optofluidic Fiber Laser Encoded with Topologically Structured Chiral Droplets

“…Wavelength-tunable OFLs have been explored and demonstrated in many platforms, for instance, by infiltrating different dyes in a single optofluidic fiber sandwiched between two dielectric mirrors (Fabry–Perot cavity). ,, In this frame, multicolored lasers are mostly achieved by combining the output beams of individual lasers, each emitting at a single color corresponding to a distinct optical gain medium. Additionally, by employing random lasing, several groups have demonstrated tunable multicolor/white lasers by either introducing red-green-blue dye into optofluidic fibers or integrating three dyes at the fiber tip. − Tunable lasing could also be achieved through optofluidic fiber ring resonators by filling different organic dyes in fiber. , Despite the progress in multicolor OFL, two major challenges remain nowadays: (1) Lack of efficient mechanism to manipulate the laser emission wavelengths; hence, a large number of dyes are required to form a multicolor laser. In other words, the color gamut is limited by the number of dyes and existing materials’ emission wavelength.…”