Multifunctional terahertz absorber based on the Dirac semimetal and vanadium dioxide

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Terahertz (THz) technology requires efficient and tunable absorption mechanisms.
• Dirac semimetals and vanadium dioxide (VO2) offer unique electronic and phase-transition properties relevant to THz applications.

Purpose of the Study:

• To propose and investigate a multifunctional THz absorber.
• To demonstrate tunable absorption (narrowband and broadband) by manipulating VO2 phase transitions.
• To explore the potential for sensing applications based on absorption characteristics.

Main Methods:

• Theoretical design and simulation of a THz absorber incorporating Dirac semimetal and VO2.
• Analysis of absorption spectra under varying temperatures to induce VO2 phase transitions (metallic and insulating states).
• Investigation of absorption modulation via changes in the Dirac semimetal's Fermi level.

Main Results:

• The proposed absorber exhibits broadband absorption (~4 THz) in the metallic state of VO2, with polarization and angle independence.
• In the insulating state, the absorber shows dual absorption peaks (>90% absorptivity) with high sensitivities (297.7 and 402 GHz/RIU), suitable for biosensing.
• Modulation of absorption is achieved by tuning the Fermi level of the Dirac semimetal.

Conclusions:

• A versatile THz absorber is realized, switchable between narrow and broadband operation.
• The device demonstrates significant potential for highly sensitive THz sensing, particularly for cell detection.
• The proposed absorber holds promise for advanced multifunctional modulated devices in the THz regime.