Quantum body scanner? What happens when vector vortex beams meet
scattering media

Date:
July 14, 2020
Source:
SPIE--International Society for Optics and Photonics
Summary:
Propagate light through any kind of medium -- be it free space
or biological tissue -- and light will scatter. Robustness to
scattering is a common requirement for communications and for
imaging systems.

Structured light, with its use of projected patterns, is resistant
to scattering, and has therefore emerged as a versatile tool. In
particular, modes of structured light carrying orbital angular
momentum (OAM) have attracted significant attention for applications
in biomedical imaging.



FULL STORY ========================================================================== Propagate light through any kind of medium -- be it free space or
biological tissue -- and light will scatter. Robustness to scattering is a common requirement for communications and for imaging systems. Structured light, with its use of projected patterns, is resistant to scattering,
and has therefore emerged as a versatile tool. In particular, modes of structured light carrying orbital angular momentum (OAM) have attracted significant attention for applications in biomedical imaging.


==========================================================================
OAM is an internal property of light conferring a characteristic doughnut
shape to the spatial profile. The polarization profile of OAM modes of
light can also be structured. Superimpose two OAM modes, and you can
get a vector vortex beam (VVB) characterized by a doughnut intensity distribution in the beam cross- section, and with spatially variant polarization. VVBs are considered suitable and advantageous for quantum applications in medical technology.

An innovative cancer scanner An international team of researchers
recently published a comprehensive study of VVB transmission in
scattering media. The team is collaborating under the aegis of the
European Union's FET-OPEN project Cancer Scan, which proposes to develop
a radically new unified technological concept of biomedical detection
deploying new ideas in quantum optics and quantum mechanics. The new
concept is based on unified transmission and detection of photons in
a three-dimensional space of orbital angular momentum, entanglement,
and hyperspectral characteristics. Theoretically, these elements can
contribute to developing a scanner that can screen for cancer and detect
it in a single scan of the body, without any risk of radiation.

As explained in their report, the team implemented a flexible platform
to generate VVBs and Gaussian beams, and investigated their propagation
through a medium that mimics the features of biological tissue. They demonstrate and analyze the degradation of both the spatial profile and polarization pattern of the different modes of light.

Ready, aim, scatter For both Gaussian beams and VVBs, the authors remark
that spatial profiles undergo an abrupt change as the concentration of the medium increases beyond 0.09%: a sudden swift decrease in contrast. The
authors observe that the change is due to the presence of a uniform
background caused by the scattered components of the beams.

Investigating the polarization profiles, they found that VVB behavior is
quite different from that of the Gaussian beams. Gaussian beams present
a uniform polarization pattern that is unaffected by the scattering
process. In contrast, VVBs present a complex distribution of polarization
on the transverse plane.

The team observed that a portion of the VVB signal becomes completely depolarized when it passes through scattering media, but a portion of
the signal preserves its structure.

These insights into how interaction with scattering media can affect the behavior of structured OAM light represent a step forward in exploring
how it may interact with biological tissue. The team hopes that their comprehensive study will stimulate further investigation into the effects
of light-scattering tissue-mimicking media, to advance the quest for
innovative biomedical detection technology.


========================================================================== Story Source: Materials provided by SPIE--International_Society_for_Optics_and_Photonics.

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Ilaria Gianani, Alessia Suprano, Taira Giordani, Nicolo` Spagnolo,
Fabio
Sciarrino, Dimitris Gorpas, Vasilis Ntziachristos, Katja Pinker,
Netanel Biton, Judy Kupferman, Shlomi Arnon. Transmission of vector
vortex beams in dispersive media. Advanced Photonics, 2020; 2
(03): 1 DOI: 10.1117/ 1.AP.2.3.036003 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200714143046.htm

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