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Ronald G Roy

Joseph B Milstein

The invention concerns materials which exhibit photonic band gaps in the near infrared and visible regions of the optical spectrum and methods of preparation of such materials.

Photonic band gap materials and method of preparation thereof

The invention concerns materials which exhibit photonic band gaps in the near infrared and visible regions of the optical spectrum and methods of preparation of such materials. The materials manufactured according to the invention are particularly suitable for use in the optical analog to semiconductor behavior, in which a photonic band gap material, or a plurality of such materials acting in concert, can be made to interact with and control light wave propagation in a manner analogous to the way that semiconductor materials can be made to interact with and control the flow of electrically charged particles, i.e., electricity, in both analog and digital applications. According to the invention it is possible to fabricate a photonic band gap material by impregnating the pores or voids contained within the volume of a specially prepared reticulated mesh, which may be made of a material with a high melting temperature such as a metal, with liquid material which melts at a temperature lower than the melting temperature of the reticulated mesh and which solidifies upon cooling. The reticulated mesh is then dissolved by simple chemical action in a liquid bath, leaving behind a solid reticulated structure composed of the solidified liquid material. In particular, the liquid material may be caused to solidify into an ordered solid such as a single crystal by the imposition of either or both a thermal gradient or a seed single crystal of the same or a closely related material.

The invention concerns the use of materials which exhibit photonic band gaps in the near infrared and visible regions of the optical spectrum as thermophotovoltaic emitter materials. The materials used according to the invention are particularly suitable for use in the conversion of thermal or heat energy into optical or light energy. U.S. Pat. No. 5,385,114, PHOTONIC BAND GAP MATERIALS AND METHOD OF PREPARATION THEREOF, was issued on Jan. 31, 1995 to the present inventors for a class of material which can be employed according to the present invention. According to the invention it is possible to employ these materials in the conversion of thermal energy to optical energy, in particular as a thermophotovoltaic emitter material, when the thermal energy is supplied by sources such as flames, sunlight or other broadband electromagnetic sources, or hot gases or fluids. By its nature, as disclosed in the earlier filings, the material emits optical or light energy in one or more narrow bands, which may be received by a sensor such as a photovoltaic cell that converts optical or light energy into electricity. In particular, certain significant benefits are obtained by use of the instant technology.

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Tewksbury, MA, United States of America

Ronald G Roy