Search results for "Scaling"
showing 10 items of 754 documents
Comprehensive Theoretical and Experimental Study of Short- and Long-Term Stability in a Passively Mode-Locked Solitonic Fiber Laser
2015
We demonstrate the short- and long-term stable operation of an all-polarization-maintained Fabry–Perot cavity passively mode-locked fiber laser. The laser operates in an all-anomalous-dispersion solitonic regime. Laser stability is studied by a variety of measurements, which confirm the high stability of the laser in the temporal and spectral–both optical and electrical-domains. Pulse durations of 540 fs, period-relative time jitters of $\sim$ 0.015‰, and long-term uninterrumped operation with 0.4% variation (standard deviation) in the average output power are obtained. The highly stable operation of the laser oscillator was maintained after amplifying the laser output with a conventional E…
Threshold of a Symmetrically Pumped Distributed Feedback Fiber Laser With a Variable Phase Shift
2008
In this paper, we study, both theoretically and experimentally, the threshold characteristics of a distributed feedback fiber laser that depend on the value of a phase shift introduced into the fiber Bragg grating structure. We show that as the phase shift possesses a noticeable birefringence, the laser oscillates at any phase shift value. We also reveal that the laser threshold is different for the cavity eigen polarizations and depends on the phase shift value. We derive a simple analytical formula to calculate the laser threshold in the case of pi phase shift; this formula can be utilized to estimate a minimal threshold value for the laser with certain active fiber and Bragg grating para…
Transverse effects in ring fiber laser multimode instabilities
2000
We study the influence of the transverse structure of pump and lasing fields and of the width of the doped region on the conditions for the appearance of the multimode instability in an ${\mathrm{Er}}^{3+}$-doped ring fiber laser. We show that the instability can be inhibited while maintaining a large output power when the radius of the doped region is a fraction of the core radius.
Short-wavelength soft-x-ray laser pumped in double-pulse single-beam non-normal incidence
2010
We demonstrated a $7.36$ nm Ni-like samarium soft-x-ray laser, pumped by $36$ J of a neodymium:glass chirped-pulse amplification laser. Double-pulse single-beam non-normal-incidence pumping was applied for efficient soft-x-ray laser generation. In this case, the applied technique included a single-optic focusing geometry for large beam diameters, a single-pass grating compressor, traveling-wave tuning capability, and an optimized high-energy laser double pulse. This scheme has the potential for even shorter-wavelength soft-x-ray laser pumping.
Unconstrained periodic boundary conditions for solid state elasticity
2004
We introduce a method to implement dynamics on an elastic lattice without imposing constraints via boundary or loading conditions. Using this method we are able to examine fracture processes in two-dimensional systems previously inaccessible for reliable computer simulations. We show the validity of the method by benchmarking and report a few preliminary results.
Highly Correlated Fermi Liquid in Heavy-Fermion Metals: Magnetic Properties
2014
In this chapter we show how the FCQPT theory works, when describing the behavior of HF metals under the application of magnetic field. We show that a large body of experimental data regarding the thermodynamic, transport and relaxation properties collected in measurements on HF metals can be well explained. It is demonstrated that the experimental data exhibit the scaling behavior.
Highly Correlated Fermi Liquid in Heavy-Fermion Metals: The Scaling Behavior
2014
In this chapter we show how the FCQPT theory works. We do that on the base of experimentally relevant examples. Namely, as noted in the Introduction (Chap. 1), the challenge for the theories is to explain the scaling behavior of the normalized effective mass \(M^*_N(y)\) displayed in Fig. 1.3. The theories analyzing only the critical exponents characterizing \(M^*_N(y)\) at \(y\gg 1\) consider only a part of the problem. In this section we analyze and derive the scaling behavior of the normalized effective mass near QCP as reported in Fig. 1.3. We start with describing magnetic field dependence of the quasiparticle effective mass in Sect. 6.1. Quasiparticle damping and the temperature depen…
Analytic gradients for the state-specific multireference coupled cluster singles and doubles model.
2009
The general theory of analytic energy gradients is presented for the state-specific multireference coupled cluster method introduced by Mukherjee and co-workers [Mol. Phys. 94, 157 (1998)], together with an implementation within the singles and doubles approximation, restricted to two closed-shell determinants and Hartree-Fock orbitals. Expressions for the energy gradient are derived based on a Lagrangian formalism and cast in a density-matrix notation suitable for implementation in standard quantum-chemical program packages. In the present implementation, we exploit a decomposition of the multireference coupled cluster gradient expressions, i.e., lambda equations and the corresponding dens…
Comment on “Scaling behavior in explosive fragmentation”
2002
We discuss the data analysis and the conclusions based upon the analysis given in the paper by Diehl et al. Following the suggestion in the Comment on our previous work by Astrom, Linna, and Timonen [Phys. Rev. E 65,048101 (2002)], we performed extensive molecular-dynamics simulations to confirm that our numerical results for the mass distribution of fragments after the "explosion" of thermalized samples are consistent with the scaling form n(m)∼m - ( α + 1 ) f(m/M 0 ), where ∫(m/M 0 ) is a cutoff function, M 0 is a cutoff parameter, and the exponent a is close to zero.
Vibrational excitations in systems with correlated disorder
2007
We investigate a $d$-dimensional model ($d$ = 2,3) for sound waves in a disordered environment, in which the local fluctuations of the elastic modulus are spatially correlated with a certain correlation length. The model is solved analytically by means of a field-theoretical effective-medium theory (self-consistent Born approximation) and numerically on a square lattice. As in the uncorrelated case the theory predicts an enhancement of the density of states over Debye's $\omega^{d-1}$ law (``boson peak'') as a result of disorder. This anomay becomes reinforced for increasing correlation length $\xi$. The theory predicts that $\xi$ times the width of the Brillouin line should be a universal …