Low-Velocity-Favored Transition Radiation.

Area of Science:

• Optics and Photonics
• Particle Physics
• Materials Science

Background:

• Transition radiation is photon emission from charged particles crossing optical interfaces.
• Typically, radiation intensity decreases as particle velocity lowers, limiting low-energy particle applications.
• Existing applications include particle identification and novel light sources.

Purpose of the Study:

• To investigate transition radiation from extremely low-velocity particles.
• To explore conditions where low-velocity particles yield comparable or higher radiation intensity than high-velocity particles.
• To understand the underlying physics of this exotic phenomenon.

Main Methods:

• Theoretical analysis of transition radiation.
• Simulation of particle interactions with an ultrathin epsilon-near-zero (ENZ) slab.
• Investigation of Ferrell-Berreman mode excitation and interference.

Main Results:

• Transition radiation from extremely low-velocity particles (v/c < 10^-3) can exhibit comparable intensity to high-energy particles (v/c = 0.999).
• Photon extraction efficiency for low-energy particles can be up to 8 orders of magnitude higher than for high-energy particles.
• This phenomenon is attributed to the interference of excited Ferrell-Berreman modes in an ultrathin ENZ slab.

Conclusions:

• Demonstrated a low-velocity-favored transition radiation phenomenon.
• Identified ultrathin ENZ slabs and Ferrell-Berreman mode interference as key mechanisms.
• Proposed potential applications in integrated light sources using low-energy electrons and detectors for beyond-standard-model particles.