Dataset associated with 'Silver-based surface plasmon waveguide for terahertz quantum cascade lasers'

This dataset contains the raw data of the publication about silver-based waveguide for THz QCLs, including waveguide analysis and experimental characteristics. Silver-based waveguides for terahertz-frequency quantum cascade lasers (THz QCLs) have been investigated, and good agreement is found between the waveguide analysis and the experimental characteristics. In the waveguide analysis, the dielectric constants of metal films are calculated based on the Drude model, in which the damping frequencies are extracted from the measured dc resistivities. The simulation shows that silver waveguides yield lower losses for THz QCLs across all practical operating temperatures and frequencies than their gold- and copper-based counterparts, both in surface-plasmon and double-metal waveguide geometries. Experimentally, we demonstrate higher operating temperatures and greater output powers when compared to identical devices fabricated with gold-based surface plasmon waveguides. The magnitude of the improvements is found to be dependent on the active-region design, such as the radiative diagonality and the doping concentration. Our results indicate that silver-based waveguides can potentially enable THz QCLs to operate at high temperature

Vibration Suppression of a 3-DOF Parallel Manipulator Based on Hybrid Negative Impulses Multi-mode Input Shaping

Abstract. The classic multi-mode negative impulses input shapers can suppress the residual vibration of the multi-mode system effectively. But when these several frequencies bandwidths and amplitudes of vibration modes are greatly different, the time delay and the suppression performances of input shapers are decreased. However, the hybrid multi-mode negative impulses input shapers can overcome the disadvantage. The hybrid double-mode negative impulses input shapers of a 3-DOF parallel manipulator and are constructed and compared with the classic multi-mode negative impulses input shapers. And the numerical simulations are shown out, for different frequencies bandwidths and amplitudes of vibration, and the hybrid multi-mode negative impulses input shapers can increase the total suppression performance of input shaper

Liquid-Crystal-Based Controllable Attenuators Operating in the 1-4 Terahertz Band

Liquid-crystal devices (LCDs) offer a potential route toward adaptive optical components for use in the < 2 THz band of the electromagnetic spectrum. We demonstrate LCDs using a commercially available material (E7), with unbiased birefringence values of 0.14-0.18 in the 0.3-4 THz band. We exploit the linear dichroism of the material to modulate the emission from a 3.4-THz quantum cascade laser by up to 40%, dependent upon both the liquid-crystal layer thickness and the bias voltage applied.Comment: 10 pages, 6 figure

Coherent imaging using laser feedback interferometry with pulsed-mode terahertz quantum cascade lasers

We report a coherent terahertz (THz) imaging system that utilises a quantum cascade laser (QCL) operating in pulsed-mode as both the source and detector. The realisation of a short-pulsed THz QCL feedback interferometer permits both high peak powers and improved thermal efficiency, which enables the cryogen-free operation of the system. In this work, we demonstrated pulsed-mode swept-frequency laser feedback interferometry experimentally. Our interferometric detection scheme not only permits the simultaneous creation of both amplitude and phase images, but inherently suppresses unwanted background radiation. We demonstrate that the proposed system utilising microsecond pulses has the potential to achieve 0.25 mega-pixel per second acquisition rates, paving the pathway to video frame rate THz imaging