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961.
Prudenzano F. Ciminelli C. D'orazio A. Petruzzelli V. De Sario M. 《Optical and Quantum Electronics》1999,31(8):655-674
The effects of anisotropic coupling on the nonlinear behavior of different LiNbO3 waveguides and couplers employing cascaded second-order nonlinearity are analyzed and the importance of leaky mode effect is shown. A set of practical coupling structures made of both symmetric and asymmetric waveguides is investigated and their performance is compared. The home-made computer-code, based on coupled wave theory and anisotropic mode propagation in the complex domain, allows an exact electromagnetic investigation of devices, taking into account both guided and leaky propagation in structures which exhibit losses, the generated second harmonic wave having leaky nature. As an example, for the well-investigated slab three layer waveguide, by taking into account the leaky nature of the generated second harmonic, the modal mismatch = 333 m–1 is obtained at the azimuthal angle m 61.9 (between the crystal optical c-axis and the propagation direction) while the angle found via the conventional approach is m 63.5. Moreover, the calculated second harmonic wave exhibits an attenuation equal to 7.44 × 10–1dB/cm that strongly influences the whole cascaded second-order phenomenon. The simulation results, for those structures in which it is possible to neglect the hybrid and leaky nature of the propagation modes, are compared with the literature data and an excellent agreement is found. 相似文献
962.
Zaihong Wang 《Proceedings of the American Mathematical Society》2003,131(2):523-531
In this paper, we study the dynamics of the mappings
where is a irrational rotation number. We prove the existence of orbits that go to infinity in the future or in the past by using the well-known Birkhoff Ergodic Theorem. Applying this conclusion, we deal with the unboundedness of solutions of Liénard equations with asymmetric nonlinearities.
where is a irrational rotation number. We prove the existence of orbits that go to infinity in the future or in the past by using the well-known Birkhoff Ergodic Theorem. Applying this conclusion, we deal with the unboundedness of solutions of Liénard equations with asymmetric nonlinearities.
963.
应用"逐差法"处理实验数据 总被引:4,自引:0,他引:4
本详尽地讨论了“逐差法”处理实验数据的理论方法并结合实例说明:如何记录数据,如何处理数据。 相似文献
964.
Third order nonlinear optical susceptibilities χ<3> of ternary Zn1−xMgxSe and Cd1−xMgxSe crystals have been measured using standard degenerate four-wave mixing (DFWM) method at 532 nm. The nonlinear transmission
technique has been applied to check if our crystals exhibit two-photon absorption. The studied Zn1−xMgxSe and Cd1−xMgxSe solid solutions were grown from the melt by the modified high-pressure Bridgman method. For both crystals the energy gap
increases with increasing Mg content.
In the case of Zn1−xMgxSe, it was found that the value of third order nonlinear optical susceptibility χ<3> decreases with increasing Mg content. An explanation of this behaviour results from the dependence of optical nonlinearities
on the energy band gap Eg of the studied crystals. In the case of Cd1txMgxSe with low content of Mg, no response was observed for the studied wavelength since the energy gap in such crystals is smaller
than the photon energy of the used laser radiation.
It was also found that the value of third order nonlinear optical susceptibility χ<3> for Cd0.70Mg0.30Se is higher than for Zn0.67Mg0.33Se. This behaviour can be understood if one take into consideration that the free carrier concentration in Cd1−xMgxSe samples is about four orders of magnitude higher than that in Zn1txMgxSe ones with comparable Mg content respectively. It is commonly known that when the electric conductivity increases, the values
of nonlinear optical properties increase.
From the performed measurements one can conclude that the incorporation of Mg as constituent into ZnSe and CdSe crystals leads
to a change of the third order nonlinear optical susceptibilities. 相似文献
965.
966.
967.
Benoy Talukdar Amitava Choudhuri U. Das 《International Journal of Theoretical Physics》2007,46(5):1229-1253
We have sought to work with an approach to Noether symmetry analysis which uses the properties of infinitesimal point transformations
in the space-time (q, t) variable to establish the association between symmetries and conservation laws of a dynamical system. In this approach symmetries
are expressed in the form of generators. We have studied the variational or Noether symmetries of two uncoupled Harmonic oscillators
and two such oscillators coupled by an interaction. Both these systems can have alternative Lagrangian representations. We
have studied in detail how the association between symmetries and conservation laws changes as one alters the analytic or
Lagrangian representation. This analysis is carried out with a view to explicitly demonstrate that the correlation between
symmetry transformation and corresponding invariant quantity depends crucially on the choice of the analytic representation.
PACS 45.20.Jj, 45.20.df, 45.20.dh 相似文献
968.
In this paper, the recent research on the enhanced Kerr nonlinearity and its application in entangled state discrimination
is reported. Two kinds of dynamics, including interacting double dark resonances and spontaneously generated coherence, are
presented to enhance the Kerr nonlinearity. The application of Kerr nonlinearity in quantum state discrimination is also discussed.
An arbitrary Greenberger-Horne-Zeilinger state can be discriminated using two-photon polarization parity detection which resorts
to cross-Kerr nonlinearity between a single-photon qubit and probe field. In addition, a scheme for Greenberger-Horne-Zeilinger
state discrimination of matter qubits is also proposed using the dipole induced transparency in a cavity-dipole system.
相似文献
969.
It is established that on an increase in the SHF radiation power for powder anthracite, a more rapid increase in the amplitude of the EPR line is observed in comparison to the case of linear absorption, whereas for carbon obtained by deposition of the products of pyrolysis of deuterobenzene (C6D6) on the surface of -Al2O3 there occurs saturation of absorption. At an air pressure of 10–3 mm Hg, saturation of resonance absorption is observed in both samples. The linear effects observed can be understood within the framework of the formalism of a three-level scheme possible in the case of the triplet ground state of the paramagnetic centers of powder anthracite. 相似文献
970.
本文研究对称线布载荷作用下圆底扁球壳的轴对称非线性弯曲和稳定性,讨论了当几何参数固定而载荷位置发生变化吋壳体的屈曲行为,以及当载荷作用位置固定而几何参数发生变化时壳体的屈曲行为,分析了屈曲模式对临界载荷的影响,并就ν=0.3的情形给出了数值结果。 相似文献