Search results for " Harmonic Generation"
showing 10 items of 100 documents
Compact setup for spin-, time-, and angle-resolved photoemission spectroscopy.
2020
Review of scientific instruments 91(6), 063001 (2020). doi:10.1063/5.0004861
Effect of sodium to barium substitution on the space charge implementation in thermally poled glasses for nonlinear optical applications
2009
Thermally poled niobium borophosphate glasses in the system 0.55(0.95-y) NaPO{sub 3}+y/2 Ba(PO{sub 3}){sub 2}+0.05Na{sub 2}B{sub 4}O{sub 7})+0.45Nb{sub 2}O{sub 5} were investigated for second order optical nonlinear (SON) properties. Bulk glasses were studied by Raman spectroscopy, thermal analysis, optical and dielectric measurements. The sodium to barium substitution does not lead to significant changes in optical properties, crystallization of glasses and coordination environment of polarizable niobium atoms. However, the ionic conductivity decreases drastically with the increase of barium concentration. Secondary ion mass spectroscopy has been used to determine the element distribution …
Wavelet analysis and HHG in nanorings: their applica-tions in logic gates and memory mass devices
2015
We study the application of one nanoring driven by a laser field in different states of polarization in logic circuits. In particular we show that assigning Boolean values to different states of the incident laser field and to the emitted signals, we can create logic gates such as OR, XOR and AND. We also show the possibility of making logic circuits such as half-adder and full-adder using one and two nanorings respectively. Using two nanorings we made the Toffoli gate. Finally we use the final angular momentum acquired by the electron to store information and hence show the possibility of using an array of nanorings as a mass memory device.
High-order harmonic generation via bound-bound transitions in an elliptically polarized laser field
2016
We use a simplified five-level system to investigate the high-order harmonic generation (HHG) spectrum emitted by an atom driven by a linearly or elliptically polarized laser field. For this model, the Schrödinger equation is exactly analytically reduced to the system of ordinary differential equations, which is solved numerically. Studying the intensity and polarization of the emitted radiation, we find that under high laser ellipticity the harmonic emission is suppressed. However, the harmonic intensity typically depends nonmonotonously on the laser ellipticity. Such anomalous behavior is very pronounced for the resonant harmonic. We offer an explanation of this behavior based on the incr…
High-pressure phase ofLaPO4studied by x-ray diffraction and second harmonic generation
2016
The pressure-induced phase transition of monazite-type ${\mathrm{LaPO}}_{4}$ at $\ensuremath{\approx}26$ GPa is studied by single-crystal x-ray diffraction and second harmonic generation (SHG) up to 31 GPa. The structure of the postmonazite phase of ${\mathrm{LaPO}}_{4}$ has been obtained and it is shown that it corresponds to a post-barite-type structure with an acentric space group $P{2}_{1}{2}_{1}{2}_{1}$. A strong increase of the SHG signal at the transition confirms that the high-pressure polymorph is noncentrosymmetric. The phase transition involves a significant discontinuous decrease of the unit-cell volume by 6%, which is mainly due to a strong contraction of the $a$ lattice parame…
Monte Carlo simulation of high‐order harmonics generation in bulk semiconductors and submicron structures
2004
To qualify the feasibility of standard semiconductor materials and Schottky‐barrier diodes (SBDs) for THz high‐order harmonic generation and extraction, the harmonic intensity, intrinsic noise and signal‐to‐noise ratio are calculated by the Monte Carlo method when a periodic high‐frequency large‐amplitude external signal is applied to a semiconductor device. Due to very high signal‐to‐noise ratio heavily doped GaAs SBDs are found to exhibit conditions for frequency mixing and harmonic extraction that are definitively superior to those of bulk materials. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Directional Second Harmonic Generation Controlled by Sub-wavelength Facets of an Organic Mesowire
2018
Directional harmonic generation is an important property characterizing the ability of nonlinear optical antennas to diffuse the signal in well-defined region of space. Herein, we show how sub-wavelength facets of an organic molecular mesowire crystal can be utilized to systematically vary the directionality of second harmonic generation (SHG) in the forward scattering geometry. We demonstrate this capability on crystalline diamonoanthraquinone (DAAQ) mesowires with subwavelength facets. We observed that the radial angles of the SHG emission can be tuned over a range of 130 degrees. This angular variation arises due to spatially distributed nonlinear dipoles in the focal volume of the excit…
Microwave harmonic emission in MgB2 superconductor: Comparison with YBA2CU3O7
2006
We report results of microwave second-harmonic generation in ceramic samples of MgB2, prepared by different methods. The SH signal has been investigated as a function of the temperature and the static magnetic field. The results are discussed in the framework of models reported in the literature. We show that the peculiarities of the SH signal are related to the specific properties of the sample. A comparison with the results obtained in ceramic and crystalline YBa2Cu3O7 shows that the second-harmonic emission in MgB2 is weaker than that observed in ceramic YBa2CuO7. (c) 2006 Wiley Periodicals, Inc.
Towards CEP stable, single-cycle pulse compression with bulk material
2010
We demonstrate both experimentally and numerically that self-steepening during propagation in a hollow-fiber followed by linear propagation through glass in the anomalous dispersion enables pulse compression down to 1.6 cycles at 1.8 µm wavelength.
Generazione di Seconda Armonica per Quasi-Phase-Matching Random in Tantalato di Litio con Poling Periodico
2009
We experimentally observed and explained bulk Second Harmonic Generation via Random Quasi-Phase-Matching, derived from a periodically poled Lithium Tantalate sample with a randomly patterned mark-to-space-ratio.