Large-area photonic circuits for terahertz detection and beam profiling

Area of Science:

• Photonics
• Terahertz technology
• Integrated optics

Background:

• Terahertz (THz) communication and spectroscopy demand low-noise, fast detectors.
• Current THz detectors are often discrete, slow, temperature-sensitive, and require precise beam focusing.
• Existing electro-optic detectors face challenges like two-photon absorption and fixed phase-matching, especially at telecom frequencies.

Purpose of the Study:

• To demonstrate an integrated photonic architecture for advanced terahertz detection.
• To overcome limitations of current terahertz detector technologies.
• To enable plug-and-play terahertz systems with enhanced performance.

Main Methods:

• Utilizing thin-film lithium niobate for an integrated photonic architecture.
• Employing electro-optic modulation of a telecom-frequency optical beam by a terahertz signal.
• Integrating a double array of terahertz antennas within a Mach-Zehnder interferometer.
• Achieving quasi-phase-matching via a periodic terahertz near-field pattern.

Main Results:

• Demonstrated an extended device collection area and boosted terahertz-optical interaction efficiency.
• Showcased custom-tailored frequency response and effective out-of-band signal suppression.
• Confirmed operation with diverse terahertz beam settings due to a large detection area.
• Reconstructed terahertz beam profiles using antenna arrays as pixels.

Conclusions:

• The integrated on-chip design in thin-film lithium niobate overcomes major limitations of previous electro-optic detectors.
• This architecture paves the way for more advanced, high-performance, on-chip terahertz systems.
• The developed detector offers a promising solution for terahertz communication and spectroscopy applications.