Development of a Generalized Theoretical Model for the Response of a Phase/Doppler Measurement System to Arbitrarily Oriented Fibers Illuminated by Gaussian Beams

We present a generalized theoretical model for the response of the phase/Doppler (P/D) measurement system to light scattered by cylindrical fibers. This theoretical model is valid for arbitrary fiber diameters and refractive indices, for Gaussian incident beams, and it accounts for arbitrary fiber orientations, fiber positions, and effects that are due to the two-dimensional receivers. The generalized P/D computer model (GPDCM) is the extension of an earlier study by the authors, combining past P/D simulation methodology with recent developments in modeling light scattering by tilted cylindrical fibers. A FORTRAN computer program that implements the GPDCM theoretical development was written and tested against known P/D results and physical expectations. To illustrate the capabilities of the GPDCM, we present computation results, comparing the effect of fiber tilt, fiber position, and receiver aperture on the performance of P/D systems configured in backscatter and sidescatter arrangements. Calculations show that the effects of fiber tilt and position are most pronounced in the backscatter P/D arrangement, resulting in broadening of the measured phase distribution. The calculated mean phase shifts, however, were found to be essentially independent of the above factors. Computational results also showed that the effect of fiber tilt and position on phase-distribution measurements can be reduced through proper choice of aperture shape and by imposition of threshold criteria on measurable signal characteristics such as the amplitude ratio and visibilities. The GPDCM provides a computational tool that will he valuable in the design, optimization, and evaluation of P/D fiber measurement systems. (C) 1998 Optical Society of America. OCIS codes: 290.0290, 280.1100, 120.3180

Development of a Generalized Theoretical Model for the Response of a Phase/Doppler Measurement System to Arbitrarily Oriented Fibers Illuminated by Gaussian Beams

We present a generalized theoretical model for the response of the phase/Doppler (P/D) measurement system to light scattered by cylindrical fibers. This theoretical model is valid for arbitrary fiber diameters and refractive indices, for Gaussian incident beams, and it accounts for arbitrary fiber orientations, fiber positions, and effects that are due to the two-dimensional receivers. The generalized P/D computer model (GPDCM) is the extension of an earlier study by the authors, combining past P/D simulation methodology with recent developments in modeling light scattering by tilted cylindrical fibers. A FORTRAN computer program that implements the GPDCM theoretical development was written and tested against known P/D results and physical expectations. To illustrate the capabilities of the GPDCM, we present computation results, comparing the effect of fiber tilt, fiber position, and receiver aperture on the performance of P/D systems configured in backscatter and sidescatter arrangements. Calculations show that the effects of fiber tilt and position are most pronounced in the backscatter P/D arrangement, resulting in broadening of the measured phase distribution. The calculated mean phase shifts, however, were found to be essentially independent of the above factors. Computational results also showed that the effect of fiber tilt and position on phase-distribution measurements can be reduced through proper choice of aperture shape and by imposition of threshold criteria on measurable signal characteristics such as the amplitude ratio and visibilities. The GPDCM provides a computational tool that will he valuable in the design, optimization, and evaluation of P/D fiber measurement systems. (C) 1998 Optical Society of America. OCIS codes: 290.0290, 280.1100, 120.3180

Lorentz Beams

A new kind of tridimensional scalar optical beams is introduced. These beams are called Lorentz beams because the form of their transverse pattern in the source plane is the product of two independent Lorentz functions. Closed-form expression of free-space propagation under paraxial limit is derived and pseudo non-diffracting features pointed out. Moreover, as the slowly varying part of these fields fulfils the scalar paraxial wave equation, it follows that there exist also Lorentz-Gauss beams, i.e. beams obtained by multipying the original Lorentz beam to a Gaussian apodization function. Although the existence of Lorentz-Gauss beams can be shown by using two different and independent ways obtained recently from Kiselev [Opt. Spectr. 96, 4 (2004)] and Gutierrez-Vega et al. [JOSA A 22, 289-298, (2005)], here we have followed a third different approach, which makes use of Lie's group theory, and which possesses the merit to put into evidence the symmetries present in paraxial Optics.Comment: 11 pages, 1 figure, submitted to Journal of Optics

Computation of light scattering from a dual-beam system

SIGLETIB Hannover: RO 2332(259) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Optimization of a laser diode anemometry system

SIGLETIB Hannover: RO 2332(239) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Fokussierungseigenschaften der zylindrischen Linsen

SIGLETIB Hannover: RO 2332(227) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Teilchengroessenbestimmung mittels eines zylindrischen Laserlicht-Wellenpaares

TIB Hannover: RO 2332(243) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman