Nanoplasmonic terahertz photoconductive switch on GaAs

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Low-temperature grown gallium arsenide (LT-GaAs) offers fast subpicosecond carrier response for terahertz photoconductive (PC) switching.
• However, LT-GaAs suffers from reduced carrier mobility and thermal conductivity compared to standard GaAs.

Purpose of the Study:

• To enhance the sensitivity and response of GaAs-based PC switches.
• To investigate the application of nanoplasmonic structures for improved terahertz detection.

Main Methods:

• Fabrication of a nanoplasmonic structure integrated with a GaAs PC switch.
• Characterization of the carrier sweep-out dynamics and detection sensitivity.
• Comparison with conventional GaAs PC switches and commercial LT-GaAs devices.

Main Results:

• Achieved subpicosecond carrier sweep-out in the nanoplasmonic GaAs PC switch.
• Observed over an order of magnitude increase in detection sensitivity.
• Demonstrated a 40-fold higher peak-to-peak response compared to conventional GaAs PC switches.
• Achieved double the response of a commercial antireflection coated LT-GaAs PC switch.

Conclusions:

• Nanoplasmonic structures significantly enhance the performance of GaAs-based PC switches.
• This approach offers a promising route to highly sensitive and fast terahertz detection.
• The developed nanoplasmonic PC switch outperforms both conventional GaAs and commercial LT-GaAs devices.