Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 9 of 9

Full-Text Articles in Physics

Color Changes In Stochastic Light Fields Propagating In Non-Kolmogorov Turbulence, Olga Korotkova, Elena Shchepakina Nov 2010

Color Changes In Stochastic Light Fields Propagating In Non-Kolmogorov Turbulence, Olga Korotkova, Elena Shchepakina

Physics Articles and Papers

The dependence of spectral shifts and switches in optical stochastic beams propagating through nonclassic turbulent medium on the slope of the power spectrum of fluctuations in the refractive index is revealed.


Spatio-Temporal Coupling Of Random Electromagnetic Pulses Interacting With Reflecting Gratings, Min Yao, Yangjian Cai, Olga Korotkova, Qiang Lin, Zhaoying Wang Oct 2010

Spatio-Temporal Coupling Of Random Electromagnetic Pulses Interacting With Reflecting Gratings, Min Yao, Yangjian Cai, Olga Korotkova, Qiang Lin, Zhaoying Wang

Physics Articles and Papers

Matrix optics is applied to a class of random, in time and space, electromagnetic pulsed beam-like (REMPB) radiation interacting with linear optical elements. A 66 order matrix describing transformation of a six-dimensional state vector including four spatial and two temporal positions within the field is used to derive conditions for spatio-temporal coupling. An example is included which deals with a spatio-temporal coupling in a typical REMPB on reflection from a reflecting grating. Electromagnetic nature of such interaction is explored via considering dependence of the degree of polarization of the reflected REMPB on its source and on the structure of the …


Propagation Factor Of A Stochastic Electromagnetic Gaussian Schell-Model Beam, Shijun Zhu, Yangjian Cai, Olga Korotkova Jun 2010

Propagation Factor Of A Stochastic Electromagnetic Gaussian Schell-Model Beam, Shijun Zhu, Yangjian Cai, Olga Korotkova

Physics Articles and Papers

Analytical formula is derived for the propagation factor (known asM2-factor) of a stochastic electromagnetic Gaussian Schell-model (EGSM) beam in free space and in turbulent atmosphere. In free space, the M2-factor of an EGSM beam is mainly determined by its initial degree of polarization, r.m.s. widths of the spectral densities and correlation coefficients, and its value remains invariant on propagation. In turbulent atmosphere, the M2-factor of an EGSM beam is also determined by the parameters of the turbulent atmosphere, and its value increases on propagation. The relative M2-factor of an EGSM beam with …


Focusing Of A Femtosecond Vortex Light Pulse Through A High Numerical Aperture Objective, Baosuan Chen, Jixiong Pu, Olga Korotkova May 2010

Focusing Of A Femtosecond Vortex Light Pulse Through A High Numerical Aperture Objective, Baosuan Chen, Jixiong Pu, Olga Korotkova

Physics Articles and Papers

We investigate the focusing properties of a femtosecond vortex light pulse focused by a high numerical aperture objective. By using the Richards-Wolf vectorial diffraction method, the intensity distribution, the velocity variation and the orbital angular momentum near the focus are studied in great detail. We have discovered that the femtosecond vortex light pulse can travel at various speeds, that is, slower or faster than light with a tight focusing system. Moreover, we have found that the numerical aperture of the focusing objective and the duration of the vortex light pulse will influence the orbital angular momentum distribution in the focused …


Second-Order Statistics Of Stochastic Electromagnetic Beams Propagating Through Non-Kolmogorov Turbulence, Elena Shchepakina, Olga Korotkova May 2010

Second-Order Statistics Of Stochastic Electromagnetic Beams Propagating Through Non-Kolmogorov Turbulence, Elena Shchepakina, Olga Korotkova

Physics Articles and Papers

We present a detailed investigation, qualitative and quantitative, on how the atmospheric turbulence with a non-Kolmogorov power spectrum affects the major statistics of stochastic electromagnetic beams, such as the spectral composition and the states of coherence and polarization. We suggest a detailed survey on how these properties evolve on propagation of beams generated by electromagnetic Gaussian Schell-model sources, depending on the fractal constant α of the atmospheric power spectrum.


Degree Of Paraxiality Of A Partially Coherent Field, Fei Wang, Yangjian Cai, Olga Korotkova May 2010

Degree Of Paraxiality Of A Partially Coherent Field, Fei Wang, Yangjian Cai, Olga Korotkova

Physics Articles and Papers

We extend the concept of the degree of paraxiality, introduced recently for monochromatic fields, to the domain of stochastic fields. As an example we analytically evaluate the degree of paraxiality for a broad class of model stochastic fields, the Gaussian Schell-model fields, without and with truncation and twist phase. The dependence of the degree of paraxiality on the size and the state of coherence of the source as well as on the truncation parameter and the magnitude of twist phase is analyzed by a number of numerical examples.


Stochastic Electromagnetic Beams In Positive-And Negative-Phase Materials, Zhisong Tong, Olga Korotkova Jan 2010

Stochastic Electromagnetic Beams In Positive-And Negative-Phase Materials, Zhisong Tong, Olga Korotkova

Physics Articles and Papers

Theoretical analysis of interaction of stochastic electromagnetic beamlike fields with positive- and negative-phase materials suggests that suitable combinations of such materials can serve as media where spectral, coherence, and polarization properties of beams can self-reconstruct.


Spectral Shifts And Switches In Random Fields Upon Interaction With Negative-Phase Materials, Zhisong Tong, Olga Korotkova Jan 2010

Spectral Shifts And Switches In Random Fields Upon Interaction With Negative-Phase Materials, Zhisong Tong, Olga Korotkova

Physics Articles and Papers

Spectral shifts in stochastic beam-like fields on interaction with layers of positive- and negative-phase materials are examined on the basis of the ABCD-matrix approach and generalized Huygens-Fresnel principle. It is found that boundaries between such materials may cause spectral switches. Effect of absorption of negative-phase materials on the beam spectrum is discussed. Our results may find applications in connection with spectrum-selection optical interconnects, spectrally encoded information transfer, image formation in systems involving negative-phase materials, and geometrically tunable metamaterials.


Theory Of Weak Scattering Of Stochastic Electromagnetic Fields From Deterministic And Random Media, Zhisong Tong, Olga Korotkova Jan 2010

Theory Of Weak Scattering Of Stochastic Electromagnetic Fields From Deterministic And Random Media, Zhisong Tong, Olga Korotkova

Physics Articles and Papers

The theory of scattering of scalar stochastic fields from deterministic and random media is generalized to the electromagnetic domain under the first-order Born approximation. The analysis allows for determining the changes in spectrum, coherence, and polarization of electromagnetic fields produced on their propagation from the source to the scattering volume, interaction with the scatterer, and propagation from the scatterer to the far field. An example of scattering of a field produced by a δ-correlated partially polarized source and scattered from a δ-correlated medium is provided.