We study the switching behavior of thin single domain magnetic elements in the presence of microwave excitation. The application of a microwave field strongly reduces the coercivity of the elements. We show that this effect is most profound at the ferromagnetic resonance frequency of the elements. Observations using time-resolved magneto-optic Kerr microscopy in combination with pulsed microwav...

The performance of newer generations of ultra high stability atomic frequency standards based on laser cooled atoms and ions appears to be limited by the local oscillator and the microwave synthesis chain. To improve this performance, the design considerations of microwave synthesizers for Cs hyperfine clock transition at 9.192 GHz that emphasize high resolution, low phase modulation (PM) and a...

We demonstrate that the stability of the current optical frequency comb generated by a Kerr-lens mode-locked femtosecond laser is limited by the microwave reference used for phase locking the comb spacing. Hence we implement precision frequency/phase control of the entire comb to the fundamental and second-harmonic frequencies of a stable cw laser without any external microwave reference. The s...

In this paper, the author proposes a technique for the generation of picosecond optical pulses using cascaded Mach-Zehnder electrooptic light intensity modulators. Each individual Mach-Zehnder modulator is driven by the same microwave signal. By providing proper dc bias to the modulators, the repetition frequency of the generated optical pulse can be made equal to twice the frequency of the app...

background: poly chlorinated biphenyls (pcbs) are the groups of organic chemical material and toxic, persistent, bio accumulate and pose a risk of causing adverse effects to human health and the environment. pcb compounds are caused the different health effects in human depending of age, sex, route of entry, intensity and frequency exposure. this study was conducted to determine the effect of m...

Many instruments can be used to measure radio frequency (RF) and microwave power. The most accurate one is a power sensor with a meter. The accuracy of RF and microwave power measurement depends on the accuracy of power sensor calibration. This chapter provides calibration methods of RF and microwave power sensor with system setup, modeling, equations, and analyses in different representations,...

A cesium fountain clock is operated utilizing a microwave oscillator that derives its frequency stability from a stable laser by means of a fiber-laser femtosecond frequency comb. This oscillator is based on the technology developed for optical clocks and replaces the quartz-based microwave oscillator commonly used in fountain clocks. As a result, a significant decrease in the frequency instabi...

In vitro studies to investigate biological effect of electromagnetic field are performed for microwave to millimeter-wave frequency band. A reliable measurement method of complex permittivity for biological cells is required for the dosimetry. The feasibility of applying the waveguide penetration (WP) method to measure complex permittivity for cells in the frequency range from microwave to mill...

The magnetic nanoparticle composite NiFe2O4 has traditionally been studied for high-frequency microwave absorption with marginal performance towards low-frequency radar bands (particularly L and S bands). Here, NiFe2O4 nanoparticles and nanohybrids using large-diameter graphene oxide (GO) sheets are prepared via solvothermal synthesis for low-frequency wide bandwidth shielding (L and S radar ba...

Gyrotron frequency amplifier has been used for the production of highly charged ion beams with high performance ECR ion sources (ECRIS) for almost 20 years. The widely used technology of microwave power coupling to the high temperature ECR plasma is still a borrowed design from the fusion machines. ECR ion source technologies and physics are advancing over the years, but the interpretation of h...