The analytical expressions for the average intensity,root mean square(RMS)beam width and angular spread of Gaussian Schell-model(GSM)beams propagating under slant atmospheric turbulence are derived,and they are used to study the influence of different propagation paths on the propagation of laser beams in atmospheric turbulence.It is shown that under the same condition,the influence of atmospheric turbulence along a downlink path on the GSM beam propagation is the smallest among the three paths.Therefore,the downlink propagation is more beneficial to the beam propagation through atmospheric turbulence compared with the uplink propagation and horizontal propagation.
A novel Mach–Zehnder(M-Z)interferometer used to measure the dispersion and phase shift of a light beam is reported.The interferometer consists of two identical beam displacing polarizers,which makes two beams of interference light pass through the same optical device and greatly improves the stability of the M-Z interferometer.The basic method of dispersion and phase measuring through the present interferometer is introduced in detail,and the actual application is demonstrated by a specific example.Because the measuring of dispersion and phase shift is the heating point in the field of optics,it is obvious that the M-Z interferometer will have important applications in aspects of optics,especially quantum optics and optical information processing.
Atomistic potentials for cupric element and cupric oxide are derived based on the analytical bond-order scheme that was presented by Brenner [Brenner D W, Erratum： Empirical potential for hydrocarbons for use in simulating the chemical vapor deposition of diamond films, Phys. Rev. B 1992, 46 1948]. In this paper, for the pure cupric element, the energy and structural parameters for several bulk phases as well as dimmer structure are well reproduced. The reference data are taken from our density functional theory calculations and the available experiments. The model potential also provides a good description of the bulk properties of various solid structures of cupric oxide compound structures, including cohesive energies, lattice parameters, and elastic constants.
In this paper, a subwavelength metal-grating assisted sensor of Kretschmann style that is capable of detecting the sample with a refractive index higher than that of the substrate is proposed. The sensor configuration is similar to the traditional Kretschmann structure, but the metal film is pattered into a grating. As a TM-polarized laser beam impinges from the substrate, a resonant dip point in reflectance curve is produced at a certain incident angle. Our studies indicate that the sensing sensitivity and resolution are affected by the grating＇s gap and period, and after these parameters havelaeen optimized, a sensing sensitivity of 51.484°/RIU is obtained with a slightly changing resolution.
