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We propose a novel method for generating terahertz (THz) waves using cascaded electro-optic modulators (EOMs), providing numerical simulations and experimental validations to demonstrate its effectiveness. The key of this technique is to…

Optics · Physics 2025-03-04 Sanghoon Chin , Ewelina Obrzud

Spintronic terahertz (THz) emitters (STE) based on the inverse spin Hall effect in ferromagnetic/heavy metal (FM/HM) heterostructures have become important sources for THz pulse generation. The design, materials and control of these…

Metasurfaces composed of planar arrays of sub-wavelength artificial structures show promise for extraordinary light manipulation; they have yielded novel ultrathin optical components such as flat lenses, wave plates, holographic surfaces…

The efficient amplification and lasing of electromagnetic radiation at terahertz (THz) frequencies is a non-trivial task achieved mainly by quantum cascade laser configurations with limited tunability and narrowband functionality. There is…

Optics · Physics 2018-11-30 Tianjing Guo , Liang Zhu , Pai-Yen Chen , Christos Argyropoulos

Electrical control of amplitude and phase of terahertz radiation (THz) is the key technological challenge for high resolution and noninvasive THz imaging. The lack of an active materials and devices hinders the realization of these imaging…

Materials Science · Physics 2018-04-24 Nurbek Kakenov , M Said Ergoktas , Osman Balci , Coskun Kocabas

Tunable lasers are essential for optical communication, spectroscopy, and precision sensing, where flexible and fast control of the laser wavelength is needed. However, conventional tunable laser systems often rely on mechanical actuation,…

While nearly single cycle THz pulse is conventionally accepted as the stimulus for the fastest and the most energy efficient control of spins in magnets, all-dielectric metasurfaces have been recently demonstrated to be the least…

Electrical control of photogenerated THz spin current pulses from a spintronic emitter has been at the forefront for the development of scalable, cost-efficient, wideband opto-spintronics devices. Artificially combined ferroelectric and…

Spintronic THz emitters, consisting of Ta/Co/Pt trilayers patterned into rectangles of lateral size in the 10 ${\mu}$m range, have been integrated in planar electromagnetic antennas of various types (dipole, bow-tie, spiral). Antenna…

We designed a cut-wire-pair metasurface that works as a transparent terahertz half-wave plate, by matching the electric and magnetic resonances of the structure. Due to the impedance matching nature of the resonances, a large transmission…

Optics · Physics 2017-01-31 Yosuke Nakata , Yudai Taira , Toshihiro Nakanishi , Fumiaki Miyamaru

Spintronic terahertz emitters (STEs) generate broadband terahertz (THz) radiation, which is essential for spectroscopy, imaging, and communication. The performances and the essential physical parameters of STE devices are linked to the…

Nonlinear metasurfaces are multifunctional photonic elements that generate and control light, enabling multiple proof-of-principle applications, such as in nonlinear holography, beam shaping, and nanoscale sources of entangled photon pairs.…

Spintronic terahertz (THz) emitters have established themselves as among the most practical broadband THz sources available, yet their performance remains fundamentally limited by the spin Hall conductivity of the nonmagnetic conversion…

Adoption of terahertz technologies is hindered by the lack of cost-effective THz sources. Here we demonstrate a fundamentally new way to generate and control THz radiation, via spatio-temporal emissivity modulation. By patterning the…

The toroidal dipole excitation is an important field for metamaterial research because of their low-loss attribute. In this study, we demonstrate numerically and experimentally, a unique polarization independent terahertz metamaterial that…

A full (2$\pi$) phase modulation is critical for efficient wavefront manipulation. In this article, a metasurface based on graphene long/short-strip resonators is used to implement a dynamic 2$\pi$ phase modulation by applying different…

Optics · Physics 2016-01-22 Liming Liu , Yair Zarate , Haroldo T. Hattori

In recent years, there has been notable advancement in programmable metasurfaces, primarily attributed to their cost-effectiveness and capacity to manipulate electromagnetic (EM) waves. Nevertheless, a significant limitation of numerous…

Optics · Physics 2023-09-11 Parsa Farzin , Amir saman Nooramin , Mohammad Soleimani

We introduce the concept of metasurface spatial processor, whose transmission is remotely and coherently controlled by the superposition of an incident wave and a control wave through the metasurface. The conceptual operation of this device…

THz-spectroscopy is an attractive imaging tool for scientific research, especially in life science, offering non-destructive interaction with matter due to its low photon energies. However, wavelengths above $100{\mu}m$ principally limit…

Terahertz (THz) Spintronic emitters based on ferromagnetic/metal junctions have become an important technology for the THz range, offering powerful and ultra-large spectral bandwidths. These developments have driven recent investigations of…