Photoconductive terahertz generation in nitrogen-doped single-crystal diamond

Area of Science:

• Solid-state physics
• Optoelectronics
• Materials science

Background:

• Terahertz (THz) radiation generation is crucial for various scientific and technological applications.
• Photoconductive antennas are common THz emitters, but often face limitations in efficiency and aperture size.
• Diamond, with its unique properties, presents a potential alternative material for THz emitter development.

Purpose of the Study:

• To demonstrate the first-time generation of terahertz radiation using a nitrogen-doped single-crystal diamond photoconductive emitter.
• To investigate the performance of diamond antennas with varying nitrogen doping levels.
• To compare the performance of diamond antennas with a conventional zinc selenide (ZnSe) antenna.

Main Methods:

• Fabrication of photoconductive antennas using nitrogen-doped single-crystal diamond substrates with varying dopant concentrations.
• Pumping the antennas using 400 nm femtosecond laser pulses.
• Measurement of terahertz waveforms and corresponding frequency spectra.
• Comparison of terahertz emission characteristics with a reference ZnSe antenna.

Main Results:

• Successful generation of terahertz radiation from nitrogen-doped diamond photoconductive emitters.
• Observation of a low saturation level in diamond substrates with high nitrogen content.
• Characterization of terahertz waveforms and spectra, revealing distinct emission properties based on doping levels.
• Demonstrated performance comparable to or exceeding reference ZnSe antennas under specific conditions.

Conclusions:

• Nitrogen-doped single-crystal diamond is a viable material for efficient terahertz radiation generation.
• The low saturation effect in high-nitrogen diamond is a key factor for high-performance emitters.
• Doped diamond shows significant potential for developing high-efficiency, large-aperture photoconductive antennas for terahertz applications.