# All-Plastic Organic Lasers with Top-Layer Polymeric Resonators: Tunable Emission through Bending and Application to Refractive Index Sensing

## TL;DR

Researchers developed flexible all-plastic organic lasers that can change their emission wavelength when bent, with potential uses in adjustable optical systems and sensing.

## Contribution

The novelty lies in creating all-plastic organic lasers with tunable emission via bending and demonstrating their use for refractive index sensing.

## Key findings

- Emission wavelength can be tuned by ~10 nm through mechanical deformation due to changes in the grating period.
- Lasers perform comparably to those on fused silica substrates but use cost-effective cellulose acetate substrates.
- Devices show potential for refractive index sensing and scalable, low-cost optical applications.

## Abstract

All-plastic thin-film organic lasers, in which all the
layers comprising
the device (active medium, resonator and substrate) are of polymeric
nature, are very interesting because they offer the possibility to
tune the emission laser wavelength through mechanical deformation
(bending). Here, we report all-plastic distributed feedback (DFB)
lasers based on top-layer dichromated gelatin resonators (one-dimensional
gratings), active layers of polystyrene doped with perylene orange
and substrates of cellulose acetate (CA), showing a successful laser
performance, comparable to devices based on fused silica substrates.
Remarkably, the emission wavelength of the prepared lasers can be
tuned by approximately 10 nm through mechanical deformation (bending)
thanks to the polymeric nature of all the layers involved in the device.
This tuning is primarily due to changes in the grating period, while
the layer thickness remains constant. The potential of the devices
for refractive index sensing is also demonstrated. These findings
highlight the potential of flexible top-layer resonator DFB lasers
for applications requiring adjustable emission wavelengths, such as
portable or adaptive optical systems. Additionally, the use of CA
substrates and simple fabrication processes make these devices cost
effective and easy to produce, opening the door to scalable and low-cost
production for various optical applications.