摘要:
Inventive systems and methods for the generation of energy using thermophotovoltaic cells are described. Also described are systems and methods for selectively emitting electromagnetic radiation from an emitter for use in thermophotovoltaic energy generation systems. In at least some of the inventive energy generation systems and methods, a voltage applied to the thermophotovoltaic cell (e.g., to enhance the power produced by the cell) can be adjusted to enhance system performance. Certain embodiments of the systems and methods described herein can be used to generate energy relatively efficiently.
摘要:
Inventive systems and methods for the generation of energy using thermophotovoltaic cells are described. Also described are systems and methods for selectively emitting electromagnetic radiation from an emitter for use in thermophotovoltaic energy generation systems. In at least some of the inventive energy generation systems and methods, a voltage applied to the thermophotovoltaic cell (e.g., to enhance the power produced by the cell) can be adjusted to enhance system performance. Certain embodiments of the systems and methods described herein can be used to generate energy relatively efficiently.
摘要:
A filter to transmit incident radiation at a predetermined incidence angle includes a plurality of photonic crystal structures disposed substantially along a surface normal direction of the filter. The photonic crystal structure includes a multilayer cell that comprises a first layer having a first dielectric permittivity, and a second layer having a second dielectric permittivity different from the first dielectric permittivity. The first layer and the second layer define a Brewster angle substantially equal to the predetermined incidence angle based on the first dielectric permittivity and the second permittivity. Each photonic crystal structure in the plurality of photonic crystal structures defines a respective bandgap, and the respective bandgaps of the plurality of photonic crystal structures, taken together, cover a continuous spectral region of about 50 nm to about 100 mm.
摘要:
A solar cell includes a thin film photovoltaic material structure used in absorbing light of a selective bandwidth. A multitude of dielectric front coatings are positioned on the thin film photovoltaic material structure so as to maximize admittance over the selected bandwidth. The thicknesses and indices of each of the front coatings are chosen by a global-optimization procedure to maximize the short-circuit current of the solar cell.
摘要:
A system and a method for generating terahertz (THz) radiation are provided. The system includes a photonic crystal structure comprising at least one nonlinear material that enables optical rectification. The photonic crystal structure is configured to have the suitable transverse dispersion relations and enhanced density photonic states so as to allow THz radiation to be emitted efficiently when an optical or near infrared pulse travels through the nonlinear part of the photonic crystal.
摘要:
A photonic crystal optical switch having a periodic dielectric structure including at least one input waveguide. First and second waveguide arms branch from the input waveguide in which the relative optical path lengths of electromagnetic radiation within the arms are controlled by stimuli. At least one output waveguide that combines the electromagnetic radiation propagating within the first and second waveguide arms.
摘要:
High index-contrast fiber waveguides, materials for forming high index-contrast fiber waveguides, and applications of high index-contrast fiber waveguides are disclosed.
摘要:
Electromagnetic radiation is input into a photonic crystal having a shock wave propagating within, wherein interactions between the shock wave and the incident electromagnetic radiation provide for the modification of frequency and bandwidth associated with input electromagnetic radiation. Modifications in frequency of the electromagnetic radiation are on the order of the gap size with 100% efficiency in some cases. Additionally, the bandwidth associated with the electromagnetic radiation is increased or decreased by orders of magnitude based on such interactions. High amplitudes are trapped at the shock front for a controllable period of time, allowing for the controlled manipulation of pulses of light. Lastly, the incorporation of deliberately designed crystal defects and non-linear materials results in the conversion of all the energy in the defect band upwards in frequency if the highest group velocity is less than the shock wave speed.
摘要:
An optical waveguide including: a dielectric core region extending along a waveguide axis; and a dielectric confinement region surrounding the core about the waveguide axis, the confinement region comprising a photonic crystal structure having a photonic band gap, wherein during operation the confinement region guides EM radiation in at least a first range of frequencies to propagate along the waveguide axis, wherein the core has an average refractive index smaller than about 1.3 for a frequency in the first range of frequencies, and wherein the core a diameter in a range between about 4 &lgr; and 80 &lgr;, wherein &lgr; is a wavelength corresponding to a central frequency in the first frequency range.
摘要:
A system for efficient generation of THz radiation is provided that includes a triply-resonant nonlinear photonic resonator coupled to at least one near-infrared (NIR) or optical waveguide and to at least one THz waveguide. The energy traveling through the at least one near-infrared (NIR) or optical waveguide is converted to THz radiation inside the triply-resonant photonic resonator via a nonlinear difference frequency generation (DFG) process.