Mid-infrared tunable absorber based on an Ag/SiO₂/VO₂/Ag/VO₂ multilayer structure and its molecular sensing...

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Vanadium dioxide (VO2) exhibits a phase transition, enabling tunable optical properties.
• Mid-infrared absorbers are crucial for sensing and thermal management applications.
• Achieving dynamic control over absorption in the mid-infrared spectrum remains a challenge.

Purpose of the Study:

• To design and simulate a tunable mid-infrared absorber based on a Ag/SiO2/VO2/Ag/VO2 multilayer structure.
• To investigate the absorption performance, thermal regulation capabilities, and sensing applications of the proposed absorber.
• To explore the impact of structural modifications on the absorber's performance.

Main Methods:

• Fabrication of a Ag/SiO2/VO2/Ag/VO2 multilayer structure using electron beam evaporation.
• Optical simulations to analyze absorption spectra and field distribution.
• Characterization of thermal regulation properties based on VO2 phase transition.
• Application of the absorber for mid-infrared spectroscopy-based molecule detection.

Main Results:

• Achieved double band strong absorption at 9.09 µm (91.8%) and 10.25 µm (98.9%).
• Demonstrated exceptional thermal regulation with a 78% heat regulation range in the mid-infrared.
• Obtained an impressive limit of detection (LOD) of 10^-7 M for CV and R6G molecules.
• Confirmed that altering the absorbing layer size enhances absorption performance.

Conclusions:

• The designed VO2-based multilayer absorber offers high, tunable absorption and excellent thermal regulation in the mid-infrared.
• The structure shows significant potential for sensitive molecular detection using mid-infrared spectroscopy.
• This work provides valuable insights for developing advanced tunable optical devices.