The focal shift for a lens of finite value of Fresnel number can be defined in terms of the second moment of the intensity distribution in transverse planes. The connection with the optical transfer function is described. The specification of the focused amplitude in terms of the fractional Fourier transform is discussed, and the connections among the fractional Fourier transform, the Wigner di...

Interface modification for control of ultrafast magnetic properties using low-dose focused ion beam irradiation is demonstrated for bilayers of two technologically important materials: Ni81Fe19 and Pt. Magnetization dynamics were studied using an all-optical time-resolved magneto-optical Kerr microscopy method. Magnetization relaxation, precession, damping and the spatial coherence of magnetiza...

"The goal of this paper is to study the nonexistence nontrivial solutions following Cauchy problem $$\left\{ \begin{array}{ll} u_{tt}+(-\Delta)^{\beta/2} u+u_{t}=\displaystyle\int_{0}^{t}\left(t-\tau \right) ^{-\gamma}\left\vert u(\tau ,\cdot) \right\vert^{p}d\tau,\\ \cr u(0,x)=u_{0}(x),\quad u_t(0,x)=u_1(x),\quad x\in\mathbb{R}^n, \end{array}\right.$$ where $p>1,\ 0<\gamma <1,\,\, \be...

In this study, a new method for the optimal design of multimode shunt-damping circuits is presented. A modification “current-flowing” shunt circuit employed to control multiple vibration modes piezoelectric laminate beam. addition resistor damping components, considers capacitances and shunting branch inductors as variables. The H? norm damped system minimized using particle swarm optimization ...

Advanced laser interferometers gravitational wave detectors may need to substantially reduce the Q-factor of test mass normal modes to eliminate parametric instability. In this paper we investigate various ring damper configurations for two different laser beam geometries. We show that there is a well defined location near the mid point of a test mass where the thermal noise degradation from th...

The CLIC machine incorporates a 20 mrad crossing angle at the IP to aid the extraction of spent beams. In order to recover the luminosity lost through the crossing angle a crab cavity is proposed to rotate the bunches prior to collision. The crab cavity is chosen to have the same frequency as the main linac (11.9942 GHz) as a compromise between size, phase stability requirements and beam loadin...

In general, microrheology is carried out using active or passive particle-tracking techniques. In the present paper, a novel technique based on the out-of-plane bending vibrations of a microcantilever beam immersed into a liquid is proposed for microrheological property measurement. We propose to analytically link the damped beam motion with the rheological properties of the fluid in order to e...

The SLAC design for a next-generation linear collider with center-of-mass energy of 0.5 to 1.0 TeV requires that multiple bunches (10) be accelerated on each RF fill. At the beam intensity (1O’O particles per bunch) and RF frequency (11 to 17 GHz) required, the beam would be highly unstable transversely. Using computer simulation and analytic models, we have studied several possible methods of ...