Terahertz Pulse Shaping and Chirality Control Using a Spintronic-Semiconductor Hybrid Emitter

Terahertz (THz) radiation, spanning from 0.3 - 30 THz, 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 [1].<br/><br/>Here, we demonstrate a hybrid THz source that overcomes this limitation by integrating two THz emitters into a single device to enable pulse shaping and chirality control of the emitted radiation without any external components [2]. The two sources are a spintronic emitter (SE) [3] and a semiconductor photoconductive antenna (PCA) [4]. The two emitters respond independently to external parameters: the PCA is controlled by the applied bias voltage while the SE is controlled by the applied magnetic field. Moreover, a dual-wavelength excitation scheme allows for control of the relative time delay between the THz emission from each constituent. These properties of the hybrid emitter enable precise control of the mixing of the two signals to control the frequency, polarization, and chirality of the overall THz radiation. This on-chip hybrid emitter thus provides a powerful platform for engineered THz radiation with wide-ranging potential applications.<br/><br/>This research was supported by NSF through the University of Delaware Materials Research Science and Engineering Center, DMR-2011824.<br/><br/>References:<br/>[1] Z. Huang, W. Wu, E. Herrmann, K. Ma, Z. A. Chase, T. A. Searles, M. B. Jungfleisch, and X. Wang, Front. Optoelectron. 17, 13 (2024).<br/>[2] W. Wu, W. Acuna, Z. Huang, X. Wang, L. Gundlach, M. F. Doty, J. M. O. Zide, and M. B. Jungfleisch, arXiv:2406.05875 (2024).<br/>[3] W. Wu, C. Y. Ameyaw, M. F. Doty, and M. B. Jungfleisch, J. Appl. Phys. 130, 091101 (2021).<br/>[4] W. Acuna, W. Wu, J. Bork, M. F. Doty, M. B. Jungfleisch, L. Gundlach, J. M. O. Zide, Adv. Funct. Mater. 2401853 (2024).