Experimental demonstration of PT-symmetric stripe lasers

TL;DR

This paper reports the first experimental demonstration of PT-symmetric stripe lasers, showing how PT symmetry can be used to control light amplification and absorption in waveguides, confirming theoretical predictions.

Contribution

The paper provides the first experimental evidence of PT-symmetric stripe lasers and explores their mode behavior under different pumping conditions.

Findings

Mode spacing doubles when waveguide is half pumped

Lasing wavelengths shift to the center of initial modes

Experimental results confirm PT-symmetry breaking

Abstract

Recently, the coexistence of parity-time (PT) symmetric laser and absorber has gained tremendous research attention. While the PT symmetric absorber has been observed in microwave metamaterials, the experimental demonstration of PT symmetric laser is still absent. Here we experimentally study PT-symmetric laser absorber in stripe waveguide. Using the concept of PT symmetry to exploit the light amplification and absorption, PT-symmetric laser absorbers have been successfully obtained. Different from the single-mode PT symmetric lasers, the PT-symmetric stripe lasers have been experimentally confirmed by comparing the relative wavelength positions and mode spacing under different pumping conditions. When the waveguide is half pumped, the mode spacing is doubled and the lasing wavelengths shift to the center of every two initial lasing modes. All these observations are consistent with the theoretical predictions and confirm the PT-symmetry breaking well.