Saturation of Kerr-lens mode locking and the self-amplitude modulation coefficient

2003 ◽  
Vol 228 (4-6) ◽  
pp. 381-388 ◽  
Author(s):  
Miguel A. Larotonda
Keyword(s):  
Amplitude Modulation ◽  
Mode Locking ◽  
The Self ◽  
Amplitude Modulation Coefficient ◽  
Modulation Coefficient

New Special Standards of the Frequency Deviation Unit and the Amplitude Modulation Coefficient Unit

2005 ◽  
Vol 48 (3) ◽  
pp. 260-262
Author(s):  
V. L. Ballo ◽  
V. B. Dobrovol’skii ◽  
A. V. Zen’kovich ◽  
V. A. Rekshinskii
Keyword(s):  
Amplitude Modulation ◽  
Frequency Deviation ◽  
Amplitude Modulation Coefficient ◽  
Modulation Coefficient

Amplitude modulation between multi-scale turbulent motions in high-Reynolds-number atmospheric surface layers

2018 ◽  
Vol 861 ◽  
pp. 585-607 ◽  
Author(s):  
Hongyou Liu ◽  
Guohua Wang ◽  
Xiaojing Zheng
Keyword(s):  
Reynolds Number ◽  
Surface Layer ◽  
Amplitude Modulation ◽  
High Reynolds Number ◽  
Quality Data ◽  
Modulation Effect ◽  
Multi Scale ◽  
Amplitude Modulation Coefficient ◽  
High Reynolds ◽  
Modulation Coefficient

Long-term measurements were performed at the Qingtu Lake Observation Array site to obtain high-Reynolds-number atmospheric surface layer flow data ($Re_{\unicode[STIX]{x1D70F}}\sim O(10^{6})$). Based on the selected high-quality data in the near-neutral surface layer, the amplitude modulation between multi-scale turbulent motions is investigated under various Reynolds number conditions. The results show that the amplitude modulation effect may exist in specific motions rather than at all length scales of motion. The most energetic motions with scales larger than the wavelength of the lower wavenumber peak in the energy spectra play a vital role in the amplitude modulation effect; the small scales shorter than the wavelength of the higher wavenumber peak are strongly modulated, whereas the motions with scales ranging between these two peaks neither contribute significantly to the amplitude modulation effect nor are strongly modulated. Based on these results, a method of decomposing the fluctuating velocity is proposed to accurately estimate the degree of amplitude modulation. The corresponding amplitude modulation coefficient is much larger than that estimated by establishing a nominal cutoff wavelength; moreover, it increases log-linearly with the Reynolds number. An empirical model is proposed to parametrize the variation of the amplitude modulation coefficient with the Reynolds number and the wall-normal distance. This study contributes to a better understanding of the interaction between multi-scale turbulent motions and the results may be used to validate and improve existing numerical models of high-Reynolds-number wall turbulence.

Nonlinear Finite Element Analysis on Statically Indeterminate Prestressed Concrete Beam

2012 ◽  
Vol 482-484 ◽  
pp. 647-650
Author(s):  
Shu Tian Fang ◽  
Ying Zhang ◽  
Wen Zhao Zhong
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Amplitude Modulation ◽  
Prestressed Concrete ◽  
Concrete Beam ◽  
Bending Moment ◽  
Ultimate Bearing Capacity ◽  
Amplitude Modulation Coefficient ◽  
Modulation Coefficient ◽  
Limiting Value

Embarked from the ductility theory, the bending moment amplitude modulation limiting value ductility expression which satisfies the bearing capacity requirements have been deduced，on the value of the bending moment amplitude modulation coefficient, the influence of the using stage crack width limiting value has been considered, and the suggesting formula of the bending moment amplitude modulation coefficient has been proposed. With the aid of APDL language in the ANSYS, the entire process force analysis to statically indeterminate prestressed concrete beam has been carried on, the finite element computed result and the experiment result has been confirmed, through the example drew correlation curve, confirmed with the experiment, the beam's ultimate bearing capacity has been discussed, and the plastic hinge's formation and the influence of moment redistribution to the ultimate bearing capacity has been analyzed.

Optimizing the Self-Amplitude Modulation of Different 2-D Saturable Absorbers for Ultrafast Mode-Locked Fiber Lasers

2019 ◽  
Vol 25 (4) ◽  
pp. 1-10 ◽  
Author(s):  
Ting-Hui Chen ◽  
Chih-Hsien Cheng ◽  
Yung-Hsiang Lin ◽  
Cheng-Ting Tsai ◽  
Yu-Chieh Chi ◽  
...  
Keyword(s):  
Amplitude Modulation ◽  
Fiber Lasers ◽  
The Self ◽  
Saturable Absorbers

scholarly journals Effects of second-order nonstationary cascaded processes on Gaussian beam propagation

1999 ◽  
Vol 17 (1) ◽  
pp. 119-128
Author(s):  
GUIDO TOCI ◽  
MATTEO VANNINI ◽  
RENZO SALIMBENI
Keyword(s):  
Gaussian Beam ◽  
Amplitude Modulation ◽  
Beam Propagation ◽  
Mode Locking ◽  
Second Order ◽  
Light Pulses ◽  
Perturbative Method ◽  
Stationary Conditions ◽  
Finite Aperture ◽  
Propagation Technique

This work proposes an analytical perturbative method describing the effects on the propagation of finite aperture beams due to the self-phase and self-amplitude modulation which result from cascaded second order interaction of ultrashort light pulses. The method merges the semi-analytical solution with a perturbative beam propagation technique, namely the Gaussian Beam Decomposition, which describes the effects of the non linear modulation on the free beam propagation. In particular we have studied the problem of the time- and intensity-dependent transmission of the pulse through slits or apertures placed along the path of the beam simulating a geometry suitable for passive laser mode-locking. Although an efficient pulse shortening action can be obtained in stationary conditions, in non stationary conditions the occurrence of an unavoidable amplitude modulation perturbs the beam propagation and reduces the temporal selectivity of the modulator.

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