Novel light emitting device with ultrafast color switching

A novel light-emitting device capable of ultrafast switching of the output wavelength is proposed and demonstrated. The device achieves an electrical modulation bandwidth in excess of 1.75 GHz at 905 nm. The device contains two light-emitting regions separated by a transition region. Minority electrons are photogenerated in the device using an external CW optical pump. The light emission color is toggled by spatially relocating minority carriers from one light-emitting region (905 run peak wavelength) to another (797 nm peak wavelength) as a result of an applied voltage.