Angular Photonic Band Gap

Applications

Angular photonic band gaps transmit or absorb electromagentic radiation based on the polarization and reflecting electromagnetic radiation of certain frequencies. Applications for this effect are found in solar energy, as this technology enables a nearly perfect greenhouse effect. Also, this invention will be useful for structures designed to "trap" light of a known incidence angle.

Problem Addressed

An issue with current technology is the low efficiency of the solar-energy conversion, which is limited by re-radiation of sunlight, consequently causing energy loss. This invention demonstrates how light close to normal incidence can be near perfectly transmitted, independent of polarization. Moreover, this invention uses photonic crystals whose constituents have an anisotropic dielectric and/or magnetic response to enable such transmission.

Technology

This invention presents a novel class of material systems that strongly discriminate light based on the angle of incidence, over a broad range of frequencies, and irrespective of the polarization. The meta-material system proposed consists of a one-dimensional periodic photonic crystal whose constituents possess anisotropic properties. This photonic material comprising of a plurality of photonic crystals can be used to selectively transmit and/or selectively absorb one portion of incoming electromagnetic radiation while reflecting another portion of incoming electromagnetic radiation. The design structure opens an angular gap for both polarizations over a certain frequency range with the possibility of enlarging the frequency range to the specific angular discrimination desired. 

Advantages

  • Reduces energy loss
  • Wider range of light that can be identified