Enhanced Terahertz Sensing via On-Chip Integration of Diffractive Optics with InGaAs Bow-Tie Detectors

Area of Science:

• Optoelectronics
• Terahertz (THz) Technology
• Integrated Optics

Background:

• Practical terahertz (THz) systems require compact, functional, and user-friendly designs.
• Current THz detectors often lack the sensitivity and integration needed for widespread application.

Purpose of the Study:

• To demonstrate single-sided integration of Fresnel zone plates with InGaAs bow-tie diodes on a semiconductor chip.
• To enhance the sensitivity and functionality of THz detection systems.

Main Methods:

• Numerical simulations to optimize Fresnel zone plate focal length and InP substrate thickness for 600 GHz operation.
• Fabrication of integrated optical elements and semiconductor detectors on a single chip.
• Characterization of detector response and sensitivity under varying conditions.

Main Results:

• Achieved room-temperature operation with a sensitivity of 24.5 V/W, an order of magnitude higher than standalone detectors.
• Demonstrated constructive interference at 600 GHz through optimized optical element design.
• Observed strong angular dependence of the detector's response to incident radiation.

Conclusions:

• Single-sided integration of flat optics with THz detectors offers improved sensitivity and simplified manufacturing.
• This approach enables more compact, cost-effective THz detection systems.
• Further development holds promise for advanced THz imaging and spectroscopy applications.