Tunable light emission from dielectric metasurfaces

Tunable and light-emitting metasurfaces have attracted increasing research interest in recent years. Here by combining liquid-crystal-integrated metasurfaces with a fluorescent substrate, we demonstrate active tuning of the emission spectrum and pattern in the red wavelength range. The measurements are performed with the techniques of momentum-space resolved spectroscopy and back-focal-plane imaging, showing a maximum of 16 nm shift of the emission wavelengths from 677 nm to 693 nm, and significant changes in the emission pattern at 660 nm. The results are further verified with numerical simulations. Our work paves the way towards actively controllable metasurface-based sources of complex light fields.