Abstract: There is provided a diffractive optical element including a substrate, and an array of optical nanoantennas arranged on the substrate, the array of optical nanoantennas being spaced apart periodically in a lateral direction for supporting a plurality of diffraction orders at a predetermined wavelength. In particular, each optical nanoantenna in the array of optical nanoantennas is configured to control distribution of electromagnetic energy from an incident light having the predetermined wavelength amongst the plurality of diffraction orders so as to promote scattering of the electromagnetic energy in at least a first direction and suppress scattering of the electromagnetic energy in at least a second direction, the first direction and the second direction corresponding to a first diffraction order and a second diffraction order of the plurality of diffraction orders, respectively.

Abstract: Various embodiments may relate to an optical device. The optical device may include a radiation collimator configured to generate a directed light beam based on omni-directional light emission. The optical device may also include one or more optical elements configured to change a parameter of the directed light beam. The radiation collimator comprises a first reflector, a second reflector and a spacer between the first reflector and the second reflector. The first reflector, the second reflector and the spacer form a resonant cavity.

Abstract: There is provided a diffractive optical element including a substrate, and an array of optical nanoantennas arranged on the substrate, the array of optical nanoantennas being spaced apart periodically in a lateral direction for supporting a plurality of diffraction orders at a predetermined wavelength. In particular, each optical nanoantenna in the array of optical nanoantennas is configured to control distribution of electromagnetic energy from an incident light having the predetermined wavelength amongst the plurality of diffraction orders so as to promote scattering of the electromagnetic energy in at least a first direction and suppress scattering of the electromagnetic energy in at least a second direction, the first direction and the second direction corresponding to a first diffraction order and a second diffraction order of the plurality of diffraction orders, respectively.