Self-healing organic-dye-based random lasers

TL;DR

This study demonstrates reversible photodegradation and self-healing in organic-dye-based random lasers, leading to enhanced emission after cycling, which could improve their durability and performance.

Contribution

It reports the first observation of reversible photodegradation in Rhodamine 6G-based random lasers, showing self-healing and increased integrated emission after degradation and recovery.

Findings

Emission broadens, redshifts, and decreases during degradation.

Post-recovery, peak emission fully recovers.

Integrated emission exceeds original after cycling.

Abstract

One of the primary difficulties in the implementation of organic-dye-based random lasers is the tendency of organic dyes to irreversibly photodecay. In this letter we report the observation of "reversible" photodegradation in a Rhodamine 6G and ZrO$_2$ nanoparticle doped polyurethane random laser. We find that during degradation the emission broadens, redshifts, and decreases in intensity. After degradation the system is observed to self-heal leading to the emission returning to its pristine intensity, giving a recovery efficiency of 100%. While the peak intensity fully recovers, the process is not strictly "reversible" as the emission after recovery is still found to be broadened and redshifted. The combination of the peak emission fully recovering and the broadening of the emission leads to a remarkable result: the random laser cycled through degradation and recovery has a greater integrated emission intensity than the pristine system.