Magnetic field-controlled large-angle negative refraction and negative reflection of terahertz waves

Area of Science:

• Physics
• Electromagnetism
• Materials Science

Background:

• Electromagnetic wave scattering from periodic structures is crucial for optical device design.
• Gyrotropic materials exhibit unique electromagnetic properties when subjected to magnetic fields.
• Controlling terahertz (THz) waves is essential for advanced communication and sensing technologies.

Purpose of the Study:

• To investigate the scattering of electromagnetic plane waves from a 1D array of gyrotropic core-shell cylinders.
• To explore the suppression of grating diffraction orders using multipole interference.
• To demonstrate the potential for THz beam steering applications.

Main Methods:

• Utilized the generalized multiparticle Mie theory.
• Analyzed indium antimonide (InSb) core-germanium (Ge) shell cylinders.
• Applied static magnetic fields below 2.3 Tesla.

Main Results:

• Demonstrated suppression of undesired grating diffraction orders through electric and magnetic multipole interference.
• Achieved nearly perfect transmission, reflection, and absorption of THz waves.
• Realized large-angle negative refraction and negative reflection.
• Achieved beam deflection angles up to 158 degrees.

Conclusions:

• Gyrotropic core-shell gratings offer a viable platform for advanced THz beam steering.
• The precise control of THz wave propagation can be achieved by tuning magnetic fields.
• This work opens possibilities for novel THz optical components and systems.