Recent advances on coherent perfect absorber-laser systems

We present recent advances in the field of coherent perfect-absorber and laser (CPAL) for different kinds of waves. We show that this intriguing effect is enabled by parity-time symmetry breaking. We first report a monochromatic electromagnetic sensor with unprecedented sensitivity. Different from exceptional point-based concept, the sensor operates via the self-dual spectral singularity of CPAL. This scheme may thus detect small perturbation including low-density gas molecules. We implement the two-port transmission line model to study its performance and a Fabry-Perot interferometric sensor will be chosen for comparison. As the sensing scheme does not rely on frequency swept measurement, it can have no limitations due to noise. 

 

Regarding acoustics, we further propose to accomplish ultra-sensitivity and robustness to noise by demonstrating a CPAL-locked sensor to detect small-scale pressure perturbations. Last but not least, the lasing operation of CPAL devices will be demonstrated theoretically and validated numerically (3D COMSOL full elasticity simulations) for bending waves propagating in thin elastic plates. The interplay between propagatating and evanescent waves represents the main peculiarity of plate-systems, and we we will provide physical arguments in this sense.