Entropy driven multi-photon frequency up-conversion

TL;DR

This paper demonstrates an entropy-driven multi-photon frequency up-conversion process that significantly enhances efficiency, surpasses black-body radiance limits, and enables new applications in thermal radiation and high-temperature chemistry at room temperature.

Contribution

It introduces a novel entropy-driven up-conversion method achieving high efficiency and radiance exceeding black-body limits, expanding possibilities for thermal radiation applications.

Findings

Achieved ten-fold frequency up-conversion with over 27% internal efficiency.

Emitted radiance exceeds the maximal black-body radiance, indicating high effective temperature.

Demonstrated potential for room-temperature high-temperature chemistry and thermal radiation applications.

Abstract

Frequency up-conversion of few low-energy photons into a single high-energy photon, greatly contributes to imaging, light sources, detection and other fields of research. However, it offers negligible efficiency when up-converting many photons. This is because coherent process are fundamentally limited due to momentum conservation requirements, while in incoherent up-conversion the finite intermediate states lifetime requires huge intensities. Thermodynamically, conventional incoherent up-conversion is driven by the internal energy of the incoming photons. However, a system can also drive work through change in its collective properties such as entropy. Here we experimentally demonstrate entropy driven ten-fold up-conversion from 10.6{\mu} to 1{\mu}m at internal efficiency above 27% and total efficiency above 10%. In addition, the emitted radiance at 1{\mu}m exceeds the maximal possible Black-Body radiance of our device, indicating emitter's effective-temperature that is considerably above the bulk-temperature. This work opens the way for up-conversion of thermal-radiation, and high-temperature chemistry done at room-temperature.