The Spectral Width of the Radiation

1972 ◽  
pp. 125-139
Author(s):  
A. M. Ratner
Keyword(s):  
Spectral Width

Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

2013 ◽  
Vol 20 (4) ◽  
pp. 555-564 ◽  
Author(s):  
Wojciech Moćko
Keyword(s):  
Test Bench ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Deformation ◽  
Spectral Width ◽  
Hopkinson Pressure Bar ◽  
Computing Environment ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact ◽  
Bench Model

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient

Achievement of 110-nm-Wide Spectral Width in Monolithic Tunnel-Junction Light-Emitting Diode

2021 ◽  
pp. 1-1
Author(s):  
Man-Fang Huang ◽  
Ya-Hsuan Shih ◽  
Jih-Yuan Chang ◽  
Yen-Lung Huang ◽  
Jinn-Kong Sheu ◽  
...  
Keyword(s):  
Tunnel Junction ◽  
Light Emitting Diode ◽  
Spectral Width ◽  
Light Emitting

scholarly journals Space-Time Coupling: Current Concept and Two Examples from Ultrafast Optics Studied Using Exact Solution of EM Equations

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 529
Author(s):  
Nikolay L. Popov ◽  
Alexander V. Vinogradov
Keyword(s):  
Wave Equations ◽  
Coherent Control ◽  
Ultrafast Optics ◽  
Spectral Width ◽  
Space Time ◽  
Current Approach ◽  
Unipolar Pulse ◽  
Number Of Cycles ◽  
Control Of Quantum Systems ◽  
Coupling Current

Current approach to space-time coupling (STC) phenomena is given together with a complementary version of the STC concept that emphasizes the finiteness of the energy of the considered pulses. Manifestations of STC are discussed in the framework of the simplest exact localized solution of Maxwell’s equations, exhibiting a “collapsing shell”. It falls onto the center, continuously deforming, and then, having reached maximum compression, expands back without losing energy. Analytical solutions describing this process enable to fully characterize the field in space-time. It allowed to express energy density in the center of collapse in the terms of total pulse energy, frequency and spectral width in the far zone. The change of the pulse shape while travelling from one point to another is important for coherent control of quantum systems. We considered the excitation of a two-level system located in the center of the collapsing EM (electromagnetic) pulse. The result is again expressed through the parameters of the incident pulse. This study showed that as it propagates, a unipolar pulse can turn into a bipolar one, and in the case of measuring the excitation efficiency, we can judge which of these two pulses we are dealing with. The obtained results have no limitation on the number of cycles in a pulse. Our work confirms the productivity of using exact solutions of EM wave equations for describing the phenomena associated with STC effects. This is facilitated by rapid progress in the search for new types of such solutions.

scholarly journals High resolution observations of spectral width features associatedwith ULF wave signatures in artificial HF radar backscatter

2004 ◽  
Vol 22 (1) ◽  
pp. 169-182 ◽  
Author(s):  
D. M. Wright ◽  
T. K. Yeoman ◽  
L. J. Baddeley ◽  
J. A. Davies ◽  
R. S. Dhillon ◽  
...  
Keyword(s):  
High Resolution ◽  
Plasma Source ◽  
Spectral Width ◽  
Hf Radar ◽  
Mhd Waves ◽  
Small Scale ◽  
Ulf Waves ◽  
Source Population ◽  
Radar Backscatter ◽  
Field Lines

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

scholarly journals Upconversion of Broadband Infrared Radiation into Visible Light for Different Pumping Parameters

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Man Nen Litvinova ◽  
Victor Krishtop ◽  
Evgeniy Tolstov ◽  
Vladimir Troilin ◽  
Larisa Alekseeva ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Visible Light ◽  
Light Beam ◽  
Infrared Radiation ◽  
Spectral Width ◽  
Uniaxial Crystal ◽  
Phase Matching ◽  
Pump Radiation ◽  
Broadband Radiation ◽  
Lithium Niobate Crystals

The influence of pump radiation parameters such as the polarization and the spectral width of infrared radiation on the conversion of broadband radiation in lithium niobate crystals was investigated. The spectra of converted radiation were calculated for two types of phase matching in the negative uniaxial crystal by taking into account the convergence of the light beam in the crystal. Experimental spectra were obtained and compared with the calculated spectra.

Note: Broadly tunable all-fiber ytterbium laser with 0.05 nm spectral width based on multimode interference filter

2014 ◽  
Vol 85 (5) ◽  
pp. 056101 ◽  
Author(s):  
Pranab K. Mukhopadhyay ◽  
Pradeep K. Gupta ◽  
Amarjeet Singh ◽  
Sunil K. Sharma ◽  
Kushvinder S. Bindra ◽  
...  
Keyword(s):  
Spectral Width ◽  
Interference Filter ◽  
Multimode Interference

scholarly journals Tunable Mechanical Filter for Longitudinal Vibrations

2007 ◽  
Vol 14 (5) ◽  
pp. 377-391 ◽  
Author(s):  
S. Asiri
Keyword(s):  
Wave Propagation ◽  
Spectral Width ◽  
Design Parameters ◽  
Vibration Source ◽  
Vibration Isolator ◽  
Force Transmission ◽  
Longitudinal Vibrations ◽  
Frequency Bands ◽  
Mechanical Filter ◽  
Vibration And Sound Radiation

This paper presents both theoretically and experimentally a new kind of vibration isolator called tunable mechanical filter which consists of four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a filter, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the “Pass Bands” and wave propagation is efficiently attenuated within other frequency bands called the “Stop Bands”. The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. The concept of this mechanical filter as presented can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

Fibre laser system providing generation of frequency-modulated pulses with a spectral width exceeding the gain linewidth

2016 ◽  
Vol 46 (12) ◽  
pp. 1092-1096 ◽  
Author(s):  
I O Zolotovskii ◽  
D A Korobko ◽  
D A Stoliarov
Keyword(s):  
Laser System ◽  
Spectral Width ◽  
Fibre Laser
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