Stokes mode Raman random lasing in a fully biocompatible medium

TL;DR

This paper reports the first demonstration of Raman random lasing in a fully biocompatible carrot medium, utilizing natural carotene and cellulose to achieve lasing with potential bio-sensing applications.

Contribution

It introduces a novel biocompatible Raman laser medium based on carrot tissue, demonstrating lasing with CW excitation and analyzing its properties for bio-optical applications.

Findings

Lasing threshold of 130 W/cm2 with linewidth narrowing

Lasing mode retains source polarization

Emission intensity shows linear temperature dependence

Abstract

We demonstrate for the first time, Raman random lasing in a continuous-wave (CW) excited, completely biocompatible and biodegradable carrot medium. The Stokes Raman mode of carotene renders carrot as a gain medium whereas random scattering in the natural fibrous cellulose of the carrot structure facilitates random lasing. CW laser induced photoluminescence(PL) threshold and linewidth analysis at the Stokes modes of carotene show a characteristic lasing action with threshold of 130 W/cm2 and linewidth-narrowing with mode Q factors (~1300). Polarization study of output modes reveals that lasing mode mostly retains the source polarization state. A clear and interesting linear temperature dependence of emission intensity is also demonstrated. Easy availability, bio-compatibility, excitation dependent emission wavelength selectivity and temperature sensitivity are hallmarks of this elegant Raman laser medium with a strong potential as an optical source for applications in bio-sensing, imaging and spectroscopy.