Spintronic terahertz emitter with integrated electromagnetic control

Abstract

Spintronic thin films are considered as one of the promising terahertz (THz) source candidates, owing to their high performance and low cost. Much effort has been made to achieve spintronic THz sources with broadband and high conversion efficiency. However, the development of spintronic THz emitters with good compatibility, low cost, and miniaturized technology still faces many challenges. Therefore, it is urgent to extend commercial and portable spintronic THz emitters to satisfy many practical applications. Herein, we design a new generation of spintronic THz emitters composed of an alternating electromagnet and a miniaturized electronic controller. Not only can this new type of spintronic THz emitter largely simplify the ancillary equipment for spintronic sources, it also has a twice larger THz signal compared to the traditional THz time-domain spectroscopy systems with a mechanical chopper. Experimental results and theoretical calculations for electromagnetic coils show that our design can stably generate THz signals that are independent of the frequency and magnetic field of alternating signals. As the spin thin film is optimized, a magnetic field as low as 75 G satisfies the requirement for high performance THz emission. Hence, not only is the efficiency of the pump power enhanced, but also the driving current in the electromagnet is decreased. We believe that it has a wide range of applications and profound implications in THz technology based on spintronic emitters in the future.

Spintronic terahertz emitters with unidirectional radiation

“…Then terahertz (THz) waves with polarization perpendicular to the magnetization direction of the FM layer will be radiated 3 . Spintronic terahertz emission with high efficiency belongs to the field of light-matter interaction in physics, and many efforts have been paid to improve the efficient THz emission of STEs [4][5][6] . However, most of these efforts aimed to the THz generation process, and little research was targeted at the control and modulation the THz waves generated by the STE to improve the THz emission process.…”

Generation of a Focused THz Vortex Beam from a Spintronic THz Emitter with a Helical Fresnel Zone Plate

“…By designing all-silicon dielectric metasurfaces, Zhang et al fabricated three TVB generators [ 14 ]. During these studies, to detect and characterize these generated TVBs, focusing and collimating are necessary [ 15 , 16 ]. However, traditional THz lenses are bulky and costly, and the generation and focus of a TVB, which are integrated into a single device, are an effect way to overcome this problem.…”