Terahertz waves emitted from an optical fiber

Area of Science:

• Optics and Photonics
• Condensed Matter Physics
• Terahertz Science and Technology

Background:

• Terahertz (THz) wave generation and detection are crucial for various scientific and technological applications.
• Conventional THz sources often require complex setups and precise alignment.
• Developing compact, alignment-free THz sources is a significant challenge.

Purpose of the Study:

• To present a simple, alignment-free method for generating terahertz waves.
• To demonstrate the application of this method in terahertz time-domain spectroscopy and near-field microscopy.
• To explore the potential for miniaturized THz systems and sub-wavelength imaging.

Main Methods:

• Utilizing the photo-Dember effect in a (100)-oriented Indium Arsenide (InAs) film.
• Coating the InAs film onto the wedged-end facet of an optical fiber.
• Guiding infrared pulses through the optical fiber to generate THz waves near a sample.
• Measuring generated THz waves with a conventional photoconductive antenna detector.

Main Results:

• Successful generation of terahertz waves using the described optical fiber-based method.
• Achieved a terahertz bandwidth of 2 THz.
• Demonstrated a spatial resolution of 180 micrometers in near-field terahertz microscopy.
• Proof-of-principle experiments for terahertz time-domain spectroscopy and microscopy were successful.

Conclusions:

• The developed method offers a simple and alignment-free approach for THz wave generation.
• The technique shows promise for sub-wavelength terahertz spectroscopic imaging by reducing resolution to the optical fiber core size.
• Potential applications include miniaturized THz systems, remote sensing, and advanced spectroscopic imaging.