High-temperature Si linear light down converter with 220% efficiency

Abstract

The authors report the fundamentals and technology of the linear light down-conversion process, which is based on the possibility of enhancing thermal emission of semiconductors in the spectral range of intraband electron transitions (midinfrared and long-wave infrared) by the shorter wavelength interband excitation. They realized conditions (the $1.15\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$ signal-in wavelength and 2- to $20\text{\ensuremath{-}}\ensuremath{\mu}\mathrm{m}$ signal-out wavelengths, $T\ensuremath{\sim}500\phantom{\rule{0.3em}{0ex}}\mathrm{K}$) when a Si device demonstrated the 220% power conversion efficiency. They discuss the concept for incoherent broadband light down-converters made of indirect bandgap semiconductors and fueled with thermal energy (controlling light with heat process).