Hybrid metasurface perfect absorbers for temperature and biosensing applications

In this work, a comprehensive study of the sensing capabilities of a hybrid metasurface perfect absorber (HMSPA) based on square meta-atoms (S-MAs) and hollow-square meta-atoms (HS-MAs) is presented. Both designs can provide >90% absorption in the narrowband region, rendering them appropriate for filtering appli-cations. The HMSPA with HS-MAs is very sensitive to slight variations in the refractive index of the ambient medium compared with S-MAs, which is ideal for biosensing applications. The sensitivity of the S-MA-based HMSPA is similar to 135 nm/RIU and can be further enhanced to 355 nm/RIU using HS-MAs. Furthermore, depositing a temperature-sensing material on the surface of the metasurface enables employing the proposed device for temperature sensing. Owing to the extraordinary thermo-optic coefficient of polydimethylsiloxane, a temperature sensitivity of -0.18 nm/degrees C is obtained for the temperature range between 20 degrees C and 60 degrees C for the HS-MA-based HMSPA. The proposed HMSPA structures can be potentially useful in filtering, biosensing, and temperature-sensing applications, offering ease of device fabrication and light coupling competencies.

Automated summary

This work presents a comprehensive study of the sensing capabilities of a hybrid metasurface perfect absorber (HMSPA) based on square meta-atoms (S-MAs) and hollow-square meta-atoms (HS-MAs). Both designs show high absorption rates in the narrowband region, making them suitable for filtering applications. The HMSPA with HS-MAs is particularly sensitive to variations in the refractive index, which is ideal for biosensing applications. Additionally, the deposition of a temperature-sensing material on the metasurface enables temperature sensing. The proposed HMSPA structures have potential applications in filtering, biosensing, and temperature sensing.