Interferometric study of the spatial structure of a light-scattering medium

The theory of light scattering by fluctuations has been extended to optically active fluids. The new feature is the "gyration parameter", a second rank asymmetric tensor, the fluctuations of which must be counted along with the familiar isotropic (scalar) and anisotropic (traceless and symmetric) fluctuations of the electric permeability tensor. Scattering equations are derived and solved in order to obtain the spectrum of scattered light. It is found that the angular dependence of scattering caused by fluctuations of permeability alone does not involve the propagation vectors of the incident or scattered fields whereas that which involves fluctuations of the gyration parameter depends explicitly upon these two vectors. This gyration tensor also has distinguishable effects upon the depolarization, ellipticity, and rotation or tilt of the scattered quasi-monochromatic light. The total intensity is resolved into a sum of five distinct contributions, each associated with different irreducible components of the gyration and permeability tensors and each with a different dependence upon the scattering angle and polarizations of the incident and scattered light. Experiments are suggested which emphasize effects originating from the optical activity of the scattering medium.

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Spectroscopic three-dimensional imaging of light scattering medium by detection of ultrasonic velocity change due to light illumination

IEEE Ultrasonics Symposium, 2005. ◽

10.1109/ultsym.2005.1603120 ◽

2006 ◽

Author(s):

H. Horinaka ◽

T. Ura ◽

Y. Nakatani ◽

K. Wada ◽

T. Matsunaka

Keyword(s):

Light Scattering ◽

Ultrasonic Velocity ◽

Three Dimensional ◽

Light Illumination ◽

Scattering Medium ◽

Velocity Change ◽

Three Dimensional Imaging

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Detection of nanoparticles suspended in a light scattering medium

Scientific Reports ◽

10.1038/s41598-021-99768-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yan Ye ◽

David Y. H. Pui

Keyword(s):

Light Scattering ◽

Visible Light ◽

Light Wave ◽

Incident Light ◽

Scattering Medium ◽

Light Interference ◽

Potential Applications ◽

Power Frequency ◽

Suspended Nanoparticles ◽

Incident Light Wave

AbstractIntentionally intensifying the light scattering of medium molecules can allow the detection of suspended nanoparticles under conditions not suitable for conventional optical microscopies or laser particle counters. Here, we demonstrate how the collective light scattering of medium molecules and nanoparticles is imaged in response to the power, frequency, and oscillating direction of the incident light wave electric field, and how this response can be used to distinguish between nanoparticles and microparticles, such as viruses or bacteria. Under conditions that the medium light scattering is intensified, suspended nanoparticles appear as magnified shiny moving dots superimposed on the quasi-steady background of medium light scattering. Utilizing the visual enlargement resulted from the enhanced light scattering and possible light interference, we can detect directly suspended nanoparticles that are much smaller than visible light wavelengths even in unopened water bottles or other large containers. This suggests new approaches for detecting nanoparticles with many potential applications.

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