The interaction of multiple waveguide modes with a relativistic electron beam in an overmoded, single-frequency, cyclotron autoresonance maser amplifier is analyzed using a nonlinear self-consistent model and kinetic theory. It is shown analytically, and confirmed by simulation, that all of the coupled waveguide modes grow at the spatial growth rate of the dominant unstable mode, but suffer dif...

We investigate the photoluminescence (PL) spectra and the time-resolved PL decay process from colloidal quantum dots on SiN/SiO2 wet etched via BOE (HF:NH4F:H2O). The spectrum displays multi-peak shapes that vary with irradiation time. The evolution of the spectral peaks with irradiation time and collection angle demonstrates that the strong coupling of the charged-exciton emission to the leaky...

This paper presents an on-chip device that can perform gigahertz-rate amplitude modulation and switching of broadband terahertz electromagnetic waves. The operation of the device is based on the interaction of confined THz waves in a novel slot waveguide with an electronically tunable two dimensional electron gas (2DEG) that controls the loss of the THz wave propagating through this waveguide. ...

We characterize a heterodyne receiver based on a surface-plasmon waveguide quantum cascade laser (QCL) emitting at 2.84 THz as a local oscillator, and an NbN hot electron bolometer as a mixer. We find that the envelope of the far-field pattern of the QCL is diffraction-limited and superimposed onto interference fringes, which are similar to those found in narrow double-metal waveguide QCLs. Com...

A study of the surface modification induced by single femtosecond laser pulses in phosphate glass has revealed surface swelling at fluences just below the ablation threshold. This behavior is different from that observed in other dielectric materials. Optical micrographs obtained with monochromatic light show a pattern of Newton rings within the swollen region whose number scales inversely with...

Despite the difficulty in fabrication, resonant tunneling diodes ~RTD! have found a great deal of usage in the analog, digital, and mixed signal realms as a means of increasing the speed of signal processing circuitry or in reducing the static power dissipation in the circuitry. Nevertheless, RTDs suffer from their nonplanar structure. In this paper, we present a planar diode which operates via...

Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip. This is particularly useful for applications that require high-field pulses. However, the generation of strong terahertz surface waves on a wire waveguide remains a challenge. Here, ultrafast field propagation along a metal wire...

Following Hestenes and others we explore the possibility that the electron is a (sort of) bound electromagnetic wave. To do this a waveguide analogy is considered. The E, H field components in waveguide satisfy the second order Klein Gordon equation. The question is if a (first order) Dirac equation is involved. Making use of Clifford Algebra, by first it is shown that a spinor ψ satisfying Dir...

Microwave reflection is observed on a relativistic electron beam front propagating into a gas filled waveguide. The frequency conversion from the incident X band electromagnetic waves and the reflected Kd band signal is consistent with the value of the beam front velocity measured from time of flight using B03B8 probes. The reflection is found to occur during the current rise time. LE JOURNAL D...

We report room temperature demonstration of slow light propagation via coherent population oscillation (CPO) in a GaAs quantum well waveguide. Measurements of the group delay of an amplitude modulated signal resonant with the heavy-hole exciton transition reveal delays as long as 830 ps. The measured bandwidth, which approaches 100 MHz, is related to the lifetime of the photoexcited electron-ho...