Terahertz radiation generation from metallic electronic structure manipulated by inhomogeneous DC-fields

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Materials Science

Background:

• Terahertz (THz) radiation generation remains a challenge for many applications.
• Existing methods often lack efficiency or tunability.
• Controlling electronic structure (ES) offers a potential pathway for novel radiation sources.

Purpose of the Study:

• To propose a feasible and high-efficiency scheme for generating primary terahertz (THz) radiation.
• To investigate the manipulation of the electronic structure (ES) of metallic films using specifically designed DC electric and magnetic fields.
• To demonstrate the potential for controlling THz radiation properties through field parameter adjustments.

Main Methods:

• Theoretical modeling based on strict quantum theory.
• Numerical simulations to validate the proposed scheme.
• Design of spatially inhomogeneous DC magnetic fields (normal to the film) and DC electric fields (parallel to the film).

Main Results:

• The proposed DC field configuration transforms the 3D Fermi sphere into a highly-degenerate electronic structure with a pseudogap near the Fermi surface.
• Wavefunctions exhibit space-asymmetric characteristics in the modified ES.
• The pseudogap width and transition matrix elements are controllable by adjusting DC field parameters.
• Achieved pseudogap widths at the milli-electron-volt level, suitable for THz frequencies.
• Demonstrated population inversion via phonon pumping in a room-temperature environment.

Conclusions:

• The proposed method offers a viable route to high-efficiency, tunable THz radiation sources.
• Tailoring the electronic structure of metallic films with DC fields is a promising approach for THz generation.
• The findings pave the way for practical applications of THz technology in various fields.