Hybrid terahertz emitter for pulse shaping and chirality control

TL;DR

This paper introduces a hybrid terahertz emitter combining a spintronic source and a photoconductive antenna, enabling pulse shaping and chirality control without external modulators, advancing THz technology applications.

Contribution

The development of an integrated hybrid THz source that allows for on-chip control of frequency, polarization, and chirality of emitted radiation is a novel advancement.

Findings

Enables pulse shaping and chirality control of THz radiation.

Achieves precise control through dual-wavelength excitation and external tuning.

Provides a platform for engineered THz radiation with broad applications.

Abstract

Terahertz (THz) radiation, spanning from 0.3 to 3x10^12 Hz, fills the crucial gap between the microwave and infrared spectral range. THz technology has found applications in various fields, from imaging and sensing to telecommunication and biosensing. However, the full potential of these applications is often hindered by the need for precise control and manipulation of the frequency and polarization state, which typically requires external THz modulators. Here, we demonstrate a hybrid THz source that overcomes this limitation. Our device consists of two THz emitters integrated into one single device, enabling pulse shaping and chirality control of the emitted radiation without additional external components. The two sources are a spintronic emitter and a semiconductor photoconductive antenna (PCA). Using a combination of dual-wavelength excitation, allowing for control of the relative time delay between the two laser excitation pulses, and tuning external parameters for each emitter (i.e., biasing voltage for the PCA and magnetic field for the spintronic THz emitter) enables precise control of the mixing of the two signals and results in frequency, polarization, and chirality control of the overall THz radiation. This on-chip hybrid emitter provides an essential platform for engineered THz radiation with wide-ranging potential applications.