High Absorption per Unit Mass Subwavelength Structure as Uncooled Infrared Detector

A subwavelength perforated structure designed for a maximum absorption-to-mass ratio has been utilized to construct an uncooled infrared
$(\lambda \sim 8-12\ \mu \mathrm{m})$
thermal detector operating in air with a noise equivalent temperature difference (NETD) of
$23 \text{mK}$
and detectivity of
$1.1\times 10^{9}\text{cm}\sqrt{\mathrm{H}\mathrm{z}}/\mathrm{W}$
while time constant is 1.5 ms. With a fill factor of
$\sim 27\%$
, the detector shows an average absorption per unit mass of
$\sim 6.8\times 10^{12}\text{kg}^{-1}$
over the long-wave infrared regime. Mach-Zehnder interferometry has been used for optical readout of the detector.