Compact circular polarization detector with Z-shaped thermoelectric nanoantenna for infrared (IR) polarimetry

초록

The capability of infrared (IR) polarimetric imaging to enhance object detection by capturing the polarization states of emitted waves has been significantly advanced, particularly in remote sensing and biomedical imaging. While linear polarization (LP) detection has been widely implemented, circular polarization (CP) detection can expand the scope of polarimetric imaging by enabling the detection of asymmetric or anisotropic materials. However, recent advancements in IR CP detection remain challenging due to bulky designs and resolution limitations. To address these issues, a compact, high-resolution IR CP detector is proposed using a 45 degrees-tilted and asymmetric truncated dipole (Z-shaped) nanoantenna connected to a bimetal nano-thermocouple on a finite silicon dioxide substrate, operating at lambda = 10.6 mu m. The optimized structure achieves circular dichroism of 53% and directly converts IR CP waves into an output voltage (Voc) via the Seebeck effect. This device generates a Voc ratio of 2.08 between right-handed (RCP) and left-handed CP (LCP), along with a high responsivity of 1.73 V/W and a specific detectivity of 7.32 x 104 Jones, owing to its small effective area (similar to 0.5 lambda 2). The proposed device offers a compact alternative to conventional bulky IR CP detector systems and unlocks the potential for high-resolution IR polarimetric sensors.

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