Dynamically tunable multiple-polarization-sensitive black phosphorus metasurface detector operating in the...

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Polarization-sensitive photodetection is crucial for numerous advanced applications.
• Existing detectors often lack dynamic tunability and broad spectral response.

Purpose of the Study:

• To develop a dynamically tunable photodetector for mid-infrared (mid-IR) polarized light.
• To integrate black phosphorus (BP) with a phase-change material (Ge2Sb2Te5 - GST225) plasmonic metasurface.

Main Methods:

• Fabrication of a photodetector featuring a chiral gold array within a GST225 metasurface.
• Modulation of GST225 crystallization to tune the circular dichroism (CD) peak wavelength.
• Adjustment of gold array geometry to further extend the tunable CD range.
• Electrical analysis of photocurrent response to different polarization states (LCP, RCP, Lx, Ly).

Main Results:

• Achieved tunable CD peak wavelength from 3.86 μm to 4.59 μm by modulating GST225.
• Extended the tunable CD peak range from 3.42 μm to 4.71 μm by adjusting gold array geometry.
• Demonstrated high CD (>0.4) and linear dichroism (LD) (>0.42) values.
• Confirmed stable polarization response across varying incident angles and distinct photocurrents for different polarizations.

Conclusions:

• The proposed metasurface photodetector offers dynamic tunability and robust performance for mid-IR polarized light detection.
• This technology holds significant promise for applications in mid-IR sensing, imaging, and quantum technologies.