Electrically tunable perfect light absorbers as color filters and modulators

Area of Science:

• Optoelectronics
• Materials Science
• Nanotechnology

Background:

• Fabry-Perot nanocavities with semiconductor and metal films can absorb light at specific wavelengths.
• Controlling absorption wavelength typically requires altering nanocavity thickness or nanostructure patterning.
• Dynamically tuning absorption wavelength without structural modification is a significant challenge.

Purpose of the Study:

• To demonstrate an electrically tunable perfect light absorber.
• To achieve dynamic spectral control in the visible and near-infrared ranges.
• To explore applications in optical modulators and telecommunications.

Main Methods:

• Integration of ultrathin n-type doped indium antimonide into a subwavelength-thick optical nanocavity.
• Utilizing simple thin-film fabrication processes without complex nanopatterning.
• Applying bias voltage to tune the absorption wavelength.

Main Results:

• Achieved an electrically tunable perfect light absorber in the visible and near-infrared spectrum.
• Demonstrated a 40 nm spectral shift in the visible range via applied bias voltage.
• Showcased potential for optical modulation in the infrared with up to 95.3% reflectance change.

Conclusions:

• Ultrathin indium antimonide in optical nanocavities enables cost-effective, large-area tunable absorbers.
• The technology offers dynamic spectral control without structural modifications.
• The device's tunable absorption and reflectance properties are attractive for optical modulators and telecommunication switching.