All-polymer distributed Bragg reflector laser self-heals to original output power

A Bragg reflector laser is a type of solid-state dye laser, which often incurs damage due to the high excitation intensities required to operate it. This photodegradation can cause the laser to eventually fail. This issue can be avoided with a liquid-state dye laser, but these lasers are often bulky and messy.

Lu et al. developed a solid-state, all polymer dye laser that can heal itself after partial photodegradation, enabling a longer operational lifetime. The authors doped the laser in rhodamine 6g, a process known to promote healing of the damaged chromophores within the laser.

The healing process began when the laser output dropped below 32% of its initial energy. During this time, the sample was kept in the dark and the shutter closed.

The authors found the rhodamine 6g doped laser fully recovered to its original output power within 3% of experimental uncertainty.

“These lasers provide single mode operation with a gain medium that fully recovers without changes in the spectrum,” said author Nathan Dawson.

The authors noted that with continued optimization, this laser can be molded, miniaturized and integrated with other devices.

“Improving self-healing lasers starts with building a deeper understanding of the mechanisms involved in the self-healing process, so new materials and processing protocols can be developed that result in more robust lasers with higher lasing efficiency that heal at a quicker rate,” said Dawson. “The development of new materials must go hand-in-hand with optimizing the cavity to reduce the laser threshold and increase the efficiency.”

Source: “Demonstration of a self-healing all-polymer distributed Bragg reflector laser,” by Yunli Lu, Zoe Lowther, Nicholas D Christianson, Zhenpeng Li, Eric Baer, Mark G. Kuzyk, and Nathan J Dawson, Applied Physics Letters (2020). The article can be accessed at https://doi.org/10.1063/1.5145148 .