Optical force-induced nonlinearity and self-guiding of light in human red blood cell suspensions

Beam propagation in RBC suspensions

Image source: https://www.nature.com/articles/s41377-019-0142-1#Sec8

Microscopy/Imaging

Beam Propagation in RBCs

In this study, published in Light: Science and Applications, Rekha Gautam and her colleagues at the San Francisco State University and an international team of co-workers showed that a laser beam shining through red blood cell suspensions could become "self-trapped". The self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions is attributed to optical forces, particularly the forward-scattering and gradient forces. The process reduced light scattering to retain the power of the beam of laser light within the biological samples. Authors found that RBCs exhibited a strong self-focusing nonlinearity that could be chemically tuned based on the osmotic pressure. Interestingly, in aged blood samples (with lysed cells), a notably different nonlinear behavior is observed due to the presence of free hemoglobin. This work on light self-guiding through scattering bio-soft-matter may introduce new diagnostic tools for blood-related diseases.

Gautam R, Xiang Y, Lamstein J, Liang Y, Bezryadina A, Liang G, Hansson T, Wetzel B, Preece D, White A, Silverman M, Kazarian S, Xu J, Morandotti R, Chen Z (2019) Optical force-induced nonlinearity and self-guiding of light in human red blood cell suspensions. Light: Science & Applications 8: 31. (Original Publication)

https://phys.org/news/2019-03-optical-force-induced-self-guiding-human-red.html