Light down-conversion process in Si with >100 external efficiency

摘要

We report on the fundamentals and technology of Si-based linear all-optical light down-conversion process. The approach is in the possibility to enhance the thermal emission power of semiconductors in the spectral range of intraband electron transitions (mid- and long-wave infrared, free carrier absorption band) by the shorter wavelength optical pump (interband transitions, visible to near-infrared, fundamental absorption band). We experimentally realize conditions (the 1.15-μm-pump wavelength and 2 to 16-μm-signal wavelengths, T ≈ 500 K) when Si-based device demonstrated 220 % external power efficiency. As a matter of fact, we come up with new concept for high-temperature incoherent light amplifier (optical transistor) made of indirect bandgap semiconductors.