Organic Synthetic Photonic Systems with Reconfigurable Parity–Time Symmetry Breaking for Tunable Single-Mode Microlasers

摘要

Synthetic photonic materials exploiting the quantum concept of parity–time(PT) symmetry lead to an emerging photonic paradigm—non-Hermitianphotonics, which is revolutionizing the photonic sciences. The non-Hermitianphotonics dealing with the interplay between gain and loss in PT syntheticphotonic material systems offers a versatile platform for advancing microlasertechnology. However, current PT-symmetric microcavity laser systems onlymanipulate imaginary parts of the refractive indices, suffering from limited laserspectral bandwidth. Here, an organic composite material system is proposed tosynthesize reconfigurable PT-symmetric microcavities with controllable complexrefractive indices for realizing tunable single-mode laser outputs. A grayscaleelectron-beam direct-writing technique is elaborately designed to process laserdye-doped polymer films in one single step into microdisk cavities with periodicgain and loss distribution, which enables thresholdless PT-symmetry breakingand single-mode laser operation. Furthermore, organic photoisomerizable compoundsare introduced to reconfigure the PT-symmetric systems in real-time bytailoring the real refractive index of the polymer microresonators, allowing for adynamically and continuously tunable single-mode laser output. This work fundamentallyenhances the PT-symmetric photonic systems for innovative designof synthetic photonic materials and architectures.