Resonant optical cavities incorporating black phosphorus to enable electrically tunable control of light are disclosed. Methods and devices are described that use black phosphorus as an electrically tunable optical material to control phase, amplitude and/or polarization of light from visible to mid-infrared wavelengths. The operating wavelength of the optical cavities depends on the thickness of the embedded black phosphorous. Tunable control of light is performed by adjusting the doping level of black phosphorous.