Related papers: Tunable terahertz emission from difference-frequen…
We demonstrate the generation of high-quality tunable terahertz (THz) vortices in an eigenmode by employing soft-aperture difference frequency generation of a vortex output and a Gaussian mode. The generated THz vortex output exhibits a…
Intersubband response in a superlattice subjected to a homogeneous electric field (biased superlattice with equipopulated levels) is studied within the tight-binding approximation, taking into account the interplay between homogeneous and…
We report on reflective electro-optic sampling measurements of TeraHertz emission from nanometer-gate-length InGaAs-based high electron mobility transistors. The room temperature coherent gate-voltage tunable emission is demonstrated. We…
Output power of resonant-tunneling-diode (RTD) terahertz (THz) emitters can be modulated by the bias modulation similar to a semiconductor laser. This property is useful for applications of the THz waves to wireless communications and…
Structured light, particularly in the terahertz frequency range, holds considerable potential for a diverse range of applications. However, the generation and control of structured terahertz radiation pose major challenges. In this work, we…
High-power, continuously tunable narrowband terahertz (THz) sources are essential for advancing nonlinear optics, THz-driven material dynamics, and ultrafast spectroscopy. Conventional techniques typically impose a trade-off between pulse…
We consider a periodically gated two-dimensional electron system, with a central gate finger biased independently creating a tunable plasmonic cavity in a planar plasmonic crystal. We demonstrate that the plasmons resonantly excited in the…
Terahertz radiation pulses can be generated efficiently through femtosecond laser excitation of a ferromagnetic/nonmagnetic heterostructure, wherein an ultrafast laser-induced spin current results in an electromagnetic THz pulse due to…
Tunable bandpass terahertz filters are demanded in various key applications such as hyperspectral imagers, miniaturized spectrometers, and high-speed wireless communication systems. Here, a mechanically reconfigurable double-layered…
Terahertz electromagnetic radiation is extremely useful for numerous applications such as imaging and spectroscopy. Therefore, it is highly desirable to have an efficient table-top emitter covering the 1-to-30-THz window whilst being driven…
We report on the successful terahertz emission (0.6$\sim$1 THz) that is continuous and tunable in its frequency and power, by driving Josephson vortices in resonance with the collective standing Josephson plasma modes excited in stacked…
A linear regression algorithm is applied to a digital-supermode distributed Bragg reflector laser to optimise wavelength switching times. The algorithm uses the output of a digital coherent receiver as feedback to update the pre-emphasis…
We disclose an unanticipated link between plasmonics and nonlinear frequency down-conversion in laser-induced gas-plasmas. For two-color femtosecond pump pulses, a plasmonic resonance is shown to broaden the terahertz emission spectra…
We study tunable refraction of light in one-dimensional periodic lattices induced optically in a photorefractive crystal. We observe experimentally both positive and negative refraction of beams which selectively excite the first or second…
Terahertz (THz) sciences and technologies have contributed to a rapid development of a wide range of applications and expanded the frontiers in fundamental science. Spintronic terahertz emitters offer conceptual advantages since the spin…
Laser diodes with optical feedback can exhibit periodic intensity oscillations at or near the relaxation-oscillation frequency. We demonstrate optoelectronic oscillators based on external-cavity semiconductor lasers in a periodic dynamical…
Experimental results of direct measurement of resonant monochromatic terahertz emission optically excited in InGaAs transistor channels are presented. The emission is attributed to two-dimensional plasma waves excited by photogeneration of…
Intersubband transitions in a superlattice under homogeneous electric field is studied within the tight-binding approximation. Since the levels are equi-populated, the non-zero response appears beyond the Born approximation. Calculations…
At present, nearly quantum-limited heterodyne receivers for Terahertz (THz) frequencies require cooling to temperatures below 4K. We are working to build semiconductor-based "tunable antenna-coupled intersubband terahertz" (TACIT)…
We consider a high-frequency response of electrons in a single miniband of superlattice subject to dc and ac electric fields. Action of ac electric field causes oscillations of electron's effective mass in miniband, which result in a…