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Full-Text Articles in Engineering
Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao
Laser Beam Profile Deformation Effect During Bragg Acousto-Optic Interaction: A Non-Paraxial Approximation, Ray S. Huang, Chen-Wen Tarn, Partha P. Banerjee, Doungchin Cao
Electrical and Computer Engineering Faculty Publications
It is commonly known that the spatial profiles of the diffracted light beams during Bragg acousto-optic interaction are distorted due to the Bragg angle selection mechanism. All the conventional studies on this effect use the paraxial approximation. But this approximation should be amended when the incident angle of the light is large enough that the diffracted light waves do not propagate closely along the optic axis of the acousto-optic diffraction system. By using a spatial Fourier transform approach, we rigorously study the light beam profile deformation effect of the diffracted light during the Bragg acousto-optic interaction beyond the paraxial approximation. …
Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon
Guest Editorial: Special Section On Acousto-Optic Devices And Optical Information Processing: Research And Developments, Partha P. Banerjee, Ting-Chung Poon
Electrical and Computer Engineering Faculty Publications
This guest editorial provides an overview of the topical area and an introduction to the articles featured in the special section.
Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan
Examination Of Beam Propagation In Misaligned Holographic Gratings And Comparison With The Acousto-Optic Transfer Function Model For Profiled Beams, Monish Ranjan Chatterjee, David D. Reagan
Electrical and Computer Engineering Faculty Publications
A transfer function formalism developed earlier for the propagation of profiled optical beams through acousto-optic Bragg cells is revisited and applied to a thick holographic grating. The results based on the holographic coupled wave model and the acousto-optic multiple scattering model are shown to be compatible, and equivalent parameters such as the Q and grating strength are defined for the two systems. Results for a Gaussian spatial profile are numerically computed and compared. For the holographic grating, a profiled beam may be interpreted as an angular misalignment or Bragg-angle mismatch problem. The case of Bragg-wavelength mismatch is also investigated for …
A Worst-Case Analysis Of Direct-Sequence Spread-Spectrum In Multipath Channels, Murad Hizlan, Xuedong Liu
A Worst-Case Analysis Of Direct-Sequence Spread-Spectrum In Multipath Channels, Murad Hizlan, Xuedong Liu
Electrical and Computer Engineering Faculty Publications
We consider a direct-sequence spread-spectrum system operating in an indoors environment in the presence of multiaccess and multipath interference, and additive white Gaussian noise. We focus on the worst-case bit error probability of this system with a constraint on signal-to-interference ratio, and derive a Chernoff-type upper bound on this error probability. We evaluate the upper bound for a special case in order to gain understanding of the basic worst-case performance. We also compare the effects of the worst-case multipath interference with those of the worst-case multiuser interference of …
Locally Optimal, Buffer-Constrained Motion Estimation And Mode Selection For Video Sequences, C. B. Peel, Scott E. Budge, K. Liang, C.-M. Huang
Locally Optimal, Buffer-Constrained Motion Estimation And Mode Selection For Video Sequences, C. B. Peel, Scott E. Budge, K. Liang, C.-M. Huang
Electrical and Computer Engineering Faculty Publications
We describe a method of using a Lagrange multiplier to make a locally optimal trade off between rate and distortion in the motion search for video sequences, while maintaining a constant bit rate channel. Simulation of this method shows that it gives up to 3.5 dB PSNR improvement in a high motion sequence. A locally rate-distortion (R-D) optimal mode selection mechanism is also described. This method also gives significant quality benefit over the nominal method. Though the benefit of these techniques is significant when used separately, when the optimal mode selection is combined with the R-D optimal motion search, it …