  Controlling thermal emission is essential for various infrared spectroscopy
applications. Metasurfaces can be utilized to control multiple degrees of
freedom of thermal emission, enabling the compact thermal emission materials
and devices. Infrared spectroscopy such as FTIR (Fourier transform infrared
spectroscopy), usually requires external infrared radiation source and complex
spectroscopic devices for absorption spectrum measurement, which hinders the
implementation of integrated compact and portable measurement equipment.
Measuring absorption spectrum through the thermal emission of pixelated thermal
emitter array can facilitate the integration and miniaturization of measurement
setup, which is highly demanded for on-chip spectroscopy applications. Here, we
experimentally demonstrate an integrated technology that allows for indirect
measurement of the absorption spectrum through the thermal emission of
meta-cavity array. This indirect measurement method opens a new avenue for
compact infrared spectroscopy analysis.
