Ultrathin,\nDynamically Controllable Circularly Polarized\nEmission Laser Enabled by Resonant Chiral Metasurfaces

We demonstrate a simple, low-cost, and ultracompact chiral\nresonant\nmetasurface design, which, by strong local coupling to a quantum gain\nmedium (quantum emitters), allows to implement an ultrathin metasurface\nlaser, capable of generating tunable circularly polarized coherent\nlasing output. According to our detailed numerical investigations,\nthe lasing emission can be transformed from linear to circular and\nswitch from right- to left-handed circularly polarized (CP) not only\nby altering the metasurface chiral response but also by changing the\npolarization of a linearly polarized pump wave, thus enabling dynamic\nlasing-polarization control. Given the increasing interest for CP\nlaser emission, our chiral metasurface laser design proves to be a\nversatile yet straightforward strategy to generate a strong and tailored\nCP emission laser, promising great potential for future applications\nin both photonics and materials science.