Photoconductive arrays on insulating substrates for high-field terahertz generation

Area of Science:

• Terahertz (THz) science and technology
• Semiconductor device physics
• Optoelectronics

Background:

• Photoconductive arrays are crucial for generating THz radiation.
• Existing methods often require high optical pulse energies and suffer from parasitic currents.
• There is a need for more efficient and robust THz generation techniques.

Purpose of the Study:

• To design, fabricate, and characterize large-area photoconductive THz array structures.
• To investigate the generation of high-field THz radiation with reduced parasitic currents.
• To compare the performance of these novel arrays with existing THz generation methods.

Main Methods:

• Fabrication of large-area photoconductive THz arrays using LT-GaAs on an insulating substrate via wafer-scale bonding.
• Characterization of device performance, including THz field strength and bandwidth.
• Comparison with THz generation via optical rectification in ZnTe.
• Operation in an optically saturated regime to suppress laser noise.

Main Results:

• Achieved peak THz-fields as high as 120 kV/cm over a bandwidth >5 THz.
• Demonstrated efficient THz generation using lower pulse energies compared to conventional methods.
• Successfully suppressed laser noise by operating in an optically saturated regime.

Conclusions:

• The developed large-area photoconductive THz arrays offer a highly efficient method for generating strong THz fields.
• The use of an insulating substrate significantly reduces parasitic currents, enhancing device performance.
• These arrays represent a promising advancement for high-field THz applications.