scholarly journals Three-dimensional broadband light beam manipulation in forward scattering samples

2020 ◽  
Author(s):  
Payvand Arjmand ◽  
Ori Katz ◽  
Sylvain Gigan ◽  
Marc Guillon
Keyword(s):  
Light Beam ◽  
Three Dimensional ◽  
Forward Scattering ◽  
Beam Manipulation

The double-light-beam method in three-dimensional scattered-light photoelasticity

1988 ◽  
Vol 28 (1) ◽  
pp. 60-64
Author(s):  
X. -L. Liu ◽  
S. -C. Pan ◽  
L. -Z. Ha
Keyword(s):  
Light Beam ◽  
Scattered Light ◽  
Three Dimensional ◽  
Beam Method

scholarly journals Laser interferometry - Report #HT-01-2017

2021 ◽  
Author(s):  
David Naylor
Keyword(s):  
Heat Transfer ◽  
Light Beam ◽  
Three Dimensional ◽  
Local Heat Transfer ◽  
Laser Interferometry ◽  
Local Heat ◽  
Temperature Fields ◽  
Fluid Temperature ◽  
Two Dimensional ◽  
Transfer Rates

An introduction is given to the optical setup and principle of operation of classical and holographic interferometers that are used for convective he at transfer measurements. The equations for the evaluation of the temperature field are derived and methods of analysis are discussed for both two-dimensional and three-dimensional temperature fields. Emphasis is given to techniques for measuring local heat transfer rates. For two-dimensional fields, a method is presented for measuring the surface temperature gradient directly from a finite (wedge) fringe interferogram. This “direct gradient method” is shown to be most useful for the measurement of low convective heat transfer rates. For three-dimensional fields, the equations for calculating the beam-averaged local heat flux are presented. The measurement of the fluid temperature averaged along the light beam is shown to be approximate. However, an analysis is presented showing that for most cases the error associated with temperature variations in the light beam direction is small. Digital image analysis of interferograms to obtain fringe spacings is also discussed briefly.

scholarly journals Characteristic Length and Time Scales of the Highly Forward Scattering of Photons in Random Media

2019 ◽  
Vol 10 (1) ◽  
pp. 93 ◽  
Author(s):  
Hiroyuki Fujii ◽  
Moegi Ueno ◽  
Kazumichi Kobayashi ◽  
Masao Watanabe
Keyword(s):  
Radiative Transfer ◽  
Time Scales ◽  
Analytical Solutions ◽  
Random Media ◽  
Three Dimensional ◽  
Forward Scattering ◽  
Diffusion Equations ◽  
Transport Models ◽  
Photon Diffusion ◽  
Photon Transport

Background: Elucidation of the highly forward scattering of photons in random media such as biological tissue is crucial for further developments of optical imaging using photon transport models. We evaluated length and time scales of the photon scattering in three-dimensional media. Methods: We employed analytical solutions of the time-dependent radiative transfer, M-th order delta-Eddington, and photon diffusion equations (RTE, dEM, and PDE). We calculated the fluence rates at different source-detector distances and optical properties. Results: We found that the zeroth order dEM and PDE, which approximate the highly forward scattering to the isotropic scattering, are valid in longer length and time scales than approximately 10 / μ t ′ and 40 / μ t ′ v , respectively, where μ t ′ is the reduced transport coefficient and v the speed of light in a medium. The first and second order dEM, which approximate the highly forward-peaked phase function by the first two and three Legendre moments, are valid in the longer scales than approximately 4.0 / μ t ′ and 6.3 / μ t ′ v ; 2.8 / μ t ′ and 3.5 / μ t ′ v , respectively. The boundary conditions less influence the length scales, while they reduce the times scales from those for bulk at the longer length scale than approximately 4.0 / μ t ′ . Conclusion: Our findings are useful for constructions of accurate and efficient photon transport models. We evaluated length and time scales of the highly forward scattering of photons in various kinds of three-dimensional random media by analytical solutions of the radiative transfer, M-th order delta-Eddington, and photon diffusion equations.

scholarly journals Generating a three-dimensional dark focus from a single conically refracted light beam

2013 ◽  
Vol 38 (22) ◽  
pp. 4648 ◽  
Author(s):  
Yu. V. Loiko ◽  
A. Turpin ◽  
T. K. Kalkandjiev ◽  
E. U. Rafailov ◽  
J. Mompart
Keyword(s):  
Light Beam ◽  
Three Dimensional ◽  
Dark Focus
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