scholarly journals High-sensitivity plasma density retrieval in a common-path second-harmonic interferometer through simultaneous group and phase velocity measurement

2019 ◽  
Vol 26 (2) ◽  
pp. 023106 ◽  
Author(s):  
J. van Tilborg ◽  
A. J. Gonsalves ◽  
E. Esarey ◽  
C. B. Schroeder ◽  
W. P. Leemans
Keyword(s):  
Phase Velocity ◽  
Plasma Density ◽  
Velocity Measurement ◽  
Second Harmonic ◽  
High Sensitivity ◽  
Common Path ◽  
Simultaneous Group

scholarly journals Second harmonic generation correlation spectroscopy for characterizing translationally diffusing protein nanocrystals

2016 ◽  
Vol 72 (7) ◽  
pp. 849-859
Author(s):  
Ximeng Y. Dow ◽  
Christopher M. Dettmar ◽  
Emma L. DeWalt ◽  
Justin A. Newman ◽  
Alexander R. Dow ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Unit Volume ◽  
Second Harmonic ◽  
Incident Beam ◽  
High Sensitivity ◽  
Correlation Spectroscopy ◽  
Optical Process ◽  
Active Nanoparticles ◽  
Low Sensitivity

Second harmonic generation correlation spectroscopy (SHG-CS) is demonstrated as a new approach to protein nanocrystal characterization. A novel line-scanning approach was performed to enable autocorrelation analysis without sample damage from the intense incident beam. An analytical model for autocorrelation was developed, which includes a correction for the optical scattering forces arising when focusing intense, infrared beams. SHG-CS was applied to the analysis of BaTiO3nanoparticles ranging from 200 to ∼500 nm and of photosystem I nanocrystals. A size distribution was recovered for each sample and compared with the size histogram measured by scanning electron microscopy (SEM). Good agreement was observed between the two independent measurements. The intrinsic selectivity of the second-order nonlinear optical process provides SHG-CS with the ability to distinguish well ordered nanocrystals from conglomerates and amorphous aggregates. Combining the recovered distribution of particle diameters with the histogram of measured SHG intensities provides the inherent hyperpolarizability per unit volume of the SHG-active nanoparticles. Simulations suggest that the SHG activity per unit volume is likely to exhibit relatively low sensitivity to the subtle distortions within the lattice that contribute to resolution loss in X-ray diffraction, but high sensitivity to the presence of multi-domain crystals.

scholarly journals Second-harmonic generation by a chirped laser pulse with the exponential density ramp profile in the presence of a planar magnetostatic wiggler

2019 ◽  
Vol 37 (4) ◽  
pp. 442-447 ◽  
Author(s):  
Niti Kant ◽  
Arvinder Singh ◽  
Vishal Thakur
Keyword(s):  
Laser Pulse ◽  
Second Harmonic Generation ◽  
Lorentz Force ◽  
Plasma Wave ◽  
Plasma Density ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Second Order ◽  
Self Focusing ◽  
Chirped Laser Pulse

AbstractSecond-harmonic generation of the relativistic self-focused chirped laser pulse in plasma has been studied with the exponential plasma density ramp profile in the presence of a planar magnetostatic wiggler. It is evident that the exponential plasma density ramp is helpful in enhancing second-harmonic generation as, with the introduction of the exponential plasma density ramp, self-focusing becomes stronger and hence, it leads to enhance the harmonic generation of the second order in the plasma. Also, it is observed that the efficiency of second-harmonic generation enhances significantly with an increase in the value of the chirp parameter. Further, the magnetostatic wiggler helps in enhancing the harmonic generation of the second order. This is due to the fact that dynamics of the oscillating electrons is altered due to the Lorentz force which, in turn, modifies the plasma wave and, hence, results in the efficient second-harmonic generation.

scholarly journals Protein-crystal detection with a compact multimodal multiphoton microscope

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Qing-di Cheng ◽  
Hsiang-Yu Chung ◽  
Robin Schubert ◽  
Shih-Hsuan Chia ◽  
Sven Falke ◽  
...  
Keyword(s):  
Data Collection ◽  
Harmonic Generation ◽  
Diffraction Data ◽  
Second Harmonic ◽  
High Sensitivity ◽  
Protein Crystal ◽  
Third Harmonic ◽  
Increasing Demand ◽  
Biomolecular Crystallography ◽  
Nano Crystal

Abstract There is an increasing demand for rapid, effective methods to identify and detect protein micro- and nano-crystal suspensions for serial diffraction data collection at X-ray free-electron lasers or high-intensity micro-focus synchrotron radiation sources. Here, we demonstrate a compact multimodal, multiphoton microscope, driven by a fiber-based ultrafast laser, enabling excitation wavelengths at 775 nm and 1300 nm for nonlinear optical imaging, which simultaneously records second-harmonic generation, third-harmonic generation and three-photon excited ultraviolet fluorescence to identify and detect protein crystals with high sensitivity. The instrument serves as a valuable and important tool supporting sample scoring and sample optimization in biomolecular crystallography, which we hope will increase the capabilities and productivity of serial diffraction data collection in the future.

scholarly journals Large Nonlinear Kerr Angle in non-Centrosymmetric Fe/AlGaAs (001) Heterostructure

2006 ◽  
Vol 941 ◽  
Author(s):  
Haibin Zhao ◽  
Diyar Talbayev ◽  
Gunter Luepke ◽  
Aubrey Hanbicki ◽  
Connie Li ◽  
...  
Keyword(s):  
Second Harmonic ◽  
High Sensitivity ◽  
Harmonic Signal ◽  
Direct Consequence ◽  
Optical Effect ◽  
Kerr Rotation ◽  
Hard Axis ◽  
Magneto Optical Effect ◽  
Kerr Angle ◽  
Second Harmonic Signal

AbstractA large nonlinear magneto-optical effect is observed in a non-centrosymmetric Fe/AlGaAs (001) heterostructure. This effect is a direct consequence of interference between second-harmonic optical waves of magnetic and crystallographic origin, generated at ferromagnetic Fe interface and bulk AlGaAs, respectively. The longitudinal nonlinear Kerr rotation is measured to be 1.6° along the [1-10] hard axis, about two orders of magnitude stronger than the linear equivalent. The rotational second-harmonic signal shows large magnetic contrast along all the in-plane directions, demonstrating a high sensitivity to the magnetization of an anisotropic interface in the longitudinal geometry.

Validation of Dispersion Curve Reconstruction Techniques for the A0 and S0 Modes of Lamb Waves

2014 ◽  
Vol 14 (07) ◽  
pp. 1450024 ◽  
Author(s):  
Lina Draudvilienė ◽  
Renaldas Raišutis ◽  
Egidijus Žukauskas ◽  
Audrius Jankauskas
Keyword(s):  
Phase Velocity ◽  
Structural Changes ◽  
Lamb Waves ◽  
High Sensitivity ◽  
Dispersion Curves ◽  
Curve Reconstruction ◽  
Informative Signal ◽  
Zero Crossing ◽  
Reconstruction Methods ◽  
Phase Velocity Dispersion

The properties of ultrasonic Lamb waves, such as relatively small attenuation and high sensitivity to structural changes of the object being investigated, allow performing of non-destructive testing of various elongated structures like pipes, cables, etc. Due to the dispersion effect of Lamb waves, a waveform of the received informative signal is usually distorted, elongated and overlapping in the time domain. Therefore, in order to investigate objects using the ultrasonic Lamb waves and to reconstruct the dispersion curves, it is necessary to know the relationship between frequency, phase and group velocities and thickness of the plate. The zero-crossing technique for measurement of phase velocity of Lamb waves (the A0 and S0 modes) has been investigated using modelled dispersed signals and experimental signals obtained for an aluminium plate having thickness of 2 mm. A comparison between two reconstruction methods of Lamb wave phase velocity dispersion curves, namely, the two-dimensional fast Fourier transform (2D-FFT) and zero-crossing technique, along with the theoretical (analytical) dispersion curves is presented. The results indicate that the proposed zero-crossing method is suitable for use in reconstruction of dispersion curves in the regions affected by strong dispersion, especially for the A0 mode.

Study on Velocity Measurement of Gas/Solid Flow Based on Electrostatic Sensor

2014 ◽  
Vol 614 ◽  
pp. 275-278
Author(s):  
Yu Tang ◽  
Xiang Deng ◽  
Shuo Tian
Keyword(s):  
Measurement System ◽  
Velocity Measurement ◽  
Flow Measurement ◽  
Cross Correlation ◽  
Low Cost ◽  
High Sensitivity ◽  
Two Phase ◽  
Solid Flow ◽  
Correlation Algorithm ◽  
Electrostatic Induction

Electrostatic sensor is based on the principle of electrostatic induction. It is widely used for gas/solid two-phase flow measurement because it has the advantages of simple structure, high sensitivity, low cost, etc. In this paper, a velocity measurement system of gas/solid flow based on electrostatic sensor and cross-correlation algorithm is discussed. Electrostatic sensor with circular electrode is adopted. By COMSOL optimum simulation, the axial length of the electrode is designed. The signal conditioning circuits are discussed and cross-correlation algorithm is analyzed. The initial experimental results demonstrate that the velocity measurement system of gas/solid flow designed in this paper is feasible.

Sign in / Sign up

Export Citation Format

Share Document