A closed-form, two-dimensional analytical solution is developed to investigate the acoustic performance of a concentric circular Helmholtz resonator lined with fibrous material. The effect of density and the thickness of the fibrous material in the cavity is examined on the resonance frequency and the transmission loss. With the expressions for the eigenvalue and eigenfunction in the cavity, th...

The stability of a beam in an RF accelerating cavity in a storage ring or circular accelerator has been studied by K. Robinsonl* 2 and many others. Robinson has found that under certain assumptions the beam-RF system with no feedback control is stable against “center-of-charge” oscillations if the cavity resonance frequency, wo, lies in restricted ranges. In particular, if ~0 is less than the R...

Decoherence is the rapid destruction of the phase relation between two quantum states of a system caused by the entanglement of these two states with two different states of the environment [1]. The progressive decoherence of a mesoscopic Schrödinger cat has been observed for the first time in the experiment of Brune et al. [2], where the linear superposition of two coherent states of the elect...

A circular disc hitting a water surface creates an impact crater which after collapse leads to a vigorous jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in a single point halfway down the cavity. Two fast sharp-pointed jets are observed shooting up- and downwards from the closure location, which by then has turned into a stagnation point surrounded by a locally hyp...

We report continuous wave (cw) operation of a terahertz quantum-cascade vertical-external-cavity surface-emitting laser with an external cavity length approximately 30 mm, benefited by intra-cryostat focusing cavity. Compared to previous plano–plano cavities, off-axis paraboloid mirror is introduced into the as element reduce diffraction loss and enable cw lasing using small-area metasurfaces l...

We present a theoretical study of a surface plasmon ring resonator geometry that shows strong spontaneous emission control due to an extremely small optical cavity mode volume. V grooves made in the surface of a metal confine whispering gallery surface plasmon polariton modes at the bottom of the groove, with the confinement determined by groove depth and width. Resonances in ringlike cavities ...

A novel input coupler that can operate in two different frequency bands separately is proposed this paper. The dual-band (X/Ku) signals are by rectangular waveguides, respectively, particular, a Bragg reflector inserted one of the waveguides to avoid electromagnetic backflow, and then circular TE01/TE02 modes excited cylindrical cavity field diffraction through coupling holes with help coaxial ...

In this Letter the effects of the twist of fiber laser cavities on the polarization properties of the laser output are investigated experimentally and theoretically. The directions and frequencies of two laser eigenpolarization modes are found to evolve in a much more complicated way as a function of the twist rate, compared with the well-known case of polarization evolution in a twisted passiv...

Chiral coupling between quantum emitters and evanescent fields allows directional emission into nanophotonic devices is now considered to be a vital ingredient for the realization of networks. However, such requires well-defined circular dipole moment emitter---something difficult achieve solid-state at room temperature due thermal population available spin states. Here, we demonstrate that two...