Role of Active Chiral Plasmonic Phase-Change Metasurface in Tunable Photothermal Conversion and Optofluidics

Area of Science:

• Plasmonics
• Metasurfaces
• Chirality
• Phase Change Materials

Background:

• Limited research on optical chirality's impact on heat generation and fluid convection in chiral metasurfaces.
• The design framework for active devices utilizing photothermally induced fluid motion remains unexplored.

Purpose of the Study:

• To design an active chiral metasurface with tunable spectral absorption circular dichroism (CDA).
• To explore photothermally induced fluid motion using a phase change material-based metasurface.

Main Methods:

• Leveraged the reversible monoclinic-rutile phase transition in Vanadium Dioxide (VO2).
• Utilized multiphysics analysis integrating optics, thermodynamics, and hydrodynamics.
• Investigated wavelength-dependent CDA and photothermal effects.

Main Results:

• The metasurface exhibited giant, wavelength-dependent CDA in the VO2 monoclinic state, blue-shifting upon phase transition to the rutile phase.
• Demonstrated strong and tunable photothermal circular dichroism.
• Showcased tunable fluid convection velocity induced by circularly polarized (CP) excitation and VO2 phase transition.

Conclusions:

• Established a platform for tunable optofluidic circular dichroism through multiphysics analysis.
• The active chiral nanostructure enables tunable fluid convection velocity and wavelength-selective photothermal/optofluidic response.
• Paved the way for polarization-sensitive chiral absorbers, tunable photothermal systems, and reconfigurable optofluidic devices.