The interaction of relativistically strong tailored laser pulses with an atomic system is considered. Due to a special tailoring of the laser pulse, the suppression of the relativistic drift of the ionized electron and a dramatic enhancement of the rescattering probability is shown to be achievable. The high harmonic generation rate in the relativistic regime is calculated and shown to be incre...

A new nonlinear microscopy technique based on interference of backward-reflected third harmonic generation (I-THG) from multiple interfaces is presented. The technique is used to measure height variations or changes of a layer thickness with an accuracy of up to 5 nm. Height variations of a patterned glass surface and thickness variations of fibroblasts are visualized with the interferometric e...

Frequency multipliers based on superlattice (SL) devices as nonlinear elements have been developed as radiation sources for a terahertz (THz) laboratory spectrometer. Input frequencies of 100 and 250 GHz from backward wave oscillators have been multiplied up to the 11th harmonic, producing usable frequencies up to 2.7 THz. Even at these high frequencies the output power is sufficient for labora...

Three orders of magnitude in the enhancement of the third-order harmonic (TH) generation induced by the interaction of two femtosecond filaments crossing with small angles in the air is achieved. The dependences of the TH generation on the time delay, the relative polarization, the input laser intensity ratios between the probe and pump beam are measured with the crossing angle of 3.5◦, and the...

We consider elastic waves in materials with cylindrical orthotropy, this being a plausible model for wood. For time-harmonic motions, the problem is reduced to some coupled ordinary differential equations. Previously, these have been solved using the method of Frobenius (power-series expansions). We use Neumann series (expansions in Bessel functions of various orders), motivated by the known cl...

We present applications of extreme ultraviolet (XUV) single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for re...

Nonlinear magneto-optical diffraction from periodically structured samples has been studied using magnetization-induced second harmonic generation ~MSHG!. Several orders of diffraction were clearly observable in MSHG, along with a strong dependence on the magnetization. Sizeable asymmetry between the MSHG signal measured in positive and negative diffraction peaks, especially visible in second o...

This paper introduces a new generation of magnetic field sensors, based on the spherical harmonics decomposition concept. The measurement principle is similar to a spatial filtering: according to the coil shape, the sensors are just sensitive to a specific component of the multipolar expansion. Five coil shapes are determined, in order to account for the first two orders of the harmonic decompo...

In the Bio-medical environment, for the analysis of abnormality detection in the skin including skin cancer in the epidermal layer, the traditional method used is biopsy procedure. The obtained biopsy specimens are processed by various methods viz, various orders of harmonic generations enumerate certain results resulting in the chances of some unexpected infections. Later on to overcome these ...

This paper presents an IDS(VGS,VDS) model to represent PHEMT behavior in the reverse ) 0 ( < DS V , and forward zone ) 0 ( > DS V . The model predicts with high accuracy the measured data as well as higher orders derivatives of the transconductance over a large range of VDS bias. These characteristics are important for the analysis of intermodulation distortion using harmonic balance or Volterr...