Programmable random lasing pulses are highly desired due to their promising applications in information security, flexible encoding systems, and smart imaging. However, the fixed random scattering configuration hinders their realization. Herein, a programmable random laser is designed to dynamically regulate random lasing pulses through introducing an external waveguide structure with random scattering feedback. Liquid and solid film random lasers are thus separately achieved. Most importantly, various pulse time series of random lasing can be flexibly realized by switching the adhesion/separation state between the gain and the destroyed waveguide structure. The Feinam coding system is further realized for encryption and information transmission by combining programmable random pulses. The results may widely expand the application prospects of random lasers in the fields of optical data recording, dynamic security labels, smart sensing, and flexible imaging.
Random lasers with low spatial coherence have important potential applications in speckle‐free imaging and displaying. Here, an angular spectra (AS) tunable random laser is proposed through directly coupling a microcavity with a commercial optical fiber. The local in‐plane AS distributions of the random lasing can be separately tuned by selectively using coupling filtering, free transmission, and intensity modulation. The obtained random lasing has the characteristics of non‐polarization and ring AS with distribution tunability. The unique properties endow the lasing as a promising illumination source for biological imaging. An excellent image with speckle‐free and high contrast is thus achieved with a maximal contrast improvement factor of 638% relative to that under the common white lighting. The results indicate that the designed AS‐tunable random laser has great application values in the fields of biological imaging, display, integration optics, and optical physics.
Random Lasers
An angular‐spectra‐tunable random laser based on controlling the coupling length of random lasing along a commercial optical fiber is proposed by Zhaona Wang and co‐workers in article number 2200054. The random lasing with a ring angular spectra that is obtained has promise for use as an illumination source for speckle‐free biological imaging with high contrast, for applications such as imaging onion epidermal cells without the need for a dying process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.