Thin-film lithium niobate electro-optic terahertz wave detector

Area of Science:

• Optoelectronics
• Terahertz (THz) Technology
• Materials Science

Background:

• Terahertz (THz) wave detection is crucial for various scientific and technological applications.
• Existing THz detectors often face limitations in sensitivity, frequency range, or size.
• Thin-film lithium niobate on insulator (LNOI) presents unique material properties for advanced optical applications.

Purpose of the Study:

• To design, fabricate, and validate a novel electro-optic (EO) time-domain THz wave detector.
• To leverage the advantages of LNOI for enhanced THz wave detection.
• To demonstrate the performance of the LNOI-based THz detector in terms of frequency and field strength.

Main Methods:

• Fabrication of a Mach-Zehnder interferometer using thin-film LNOI optical waveguides.
• Electrical poling of interferometer arms in opposite directions for enhanced EO modulation.
• Coupling of free-space THz waves directly to the dielectric device without antennas or plasmonics.
• Validation of THz wave detection up to 800 GHz and electric fields up to 4.6 MV/m.

Main Results:

• Successful demonstration of a compact LNOI-based EO time-domain THz detector.
• Effective coupling of THz waves from free space into the device.
• Detection of THz waves with frequencies up to 800 GHz.
• Capability to detect THz electric fields as high as 4.6 MV/m.
• Experimental frequency response aligns well with theoretical predictions.

Conclusions:

• LNOI is a highly promising material for developing advanced THz wave detectors.
• The fabricated LNOI EO detector offers significant advantages in terms of size, sensitivity, and frequency range.
• This technology paves the way for improved THz sensing and measurement systems.