High-power terahertz radiation emitter with a diamond photoconductive switch array

Area of Science:

• Optics and Photonics
• Materials Science
• Solid-State Physics

Background:

• Photoconductive antennas are crucial for terahertz (THz) radiation generation.
• Current THz emitters face saturation issues limiting output power.
• High-voltage breakdown and surface flashover hinder THz emission efficiency.

Purpose of the Study:

• To develop a novel photoconductive switch-arrayed antenna for high-power THz radiation generation.
• To overcome the saturation limitations in conventional THz photoconductive antennas.
• To leverage the properties of chemical vapor-deposited diamond films for enhanced performance.

Main Methods:

• Fabrication of a photoconductive switch-arrayed antenna utilizing chemical vapor-deposited diamond film.
• Implementation of an overcoated gap structure to prevent surface flashover.
• Application of high electric field stress (up to 2 x 10^6 V/cm) across photoconductive gaps.
• Utilizing an ultrashort pulse Kr*F laser for excitation.

Main Results:

• Achieved an energy density of 10 microJ/cm^2 on the emitter surface at 10^5 V/cm.
• Demonstrated no severe saturation in photoconductive current up to 10^6 V/cm.
• Obtained higher energy density compared to current large-aperture antennas.
• Expected focused intensity of 200 MW/cm^2.

Conclusions:

• The developed diamond-based photoconductive antenna effectively generates high-power THz radiation.
• The device design overcomes saturation limitations, paving the way for more efficient THz sources.
• High breakdown threshold of diamond and advanced gap structure are key to enhanced performance.