Breaking temporal symmetries for emission and absorption

Area of Science:

• Physics
• Electromagnetics
• Thermodynamics

Background:

• Time-reversal symmetries constrain emission and absorption in reciprocal systems.
• Kirchhoff's law (e=a) limits absorber efficiency by requiring emission back to the source.
• Existing methods for breaking symmetry often involve weak modulation or mechanical motion.

Purpose of the Study:

• To theoretically and experimentally demonstrate a device with drastically different emission and absorption properties.
• To explore the potential of spatiotemporal modulation for breaking time-reversal symmetry.
• To advance applications in radiofrequency communication, energy harvesting, and thermal management.

Main Methods:

• Theoretical modeling of spatiotemporally modulated structures.
• Experimental validation of the proposed device concept.
• Analysis of emission and absorption characteristics under modulation.

Main Results:

• A spatiotemporally modulated device was designed and shown to exhibit distinct emission and absorption behaviors.
• The proposed method effectively breaks time-reversal symmetry in the system.
• Significant differences between emission and absorption properties were achieved.

Conclusions:

• Spatiotemporal modulation offers a powerful approach to decouple emission and absorption.
• This technique can overcome limitations imposed by traditional reciprocity principles.
• The findings pave the way for enhanced performance in communication, energy harvesting, and thermal management systems.