Studies of Intensity Modulated Light in Turbid Media.

Thomas M. Drane, E. A. Shapiro, Valery Milner

Eugene V. Moskovets

Bradley Worth

This thesis is divided into two parts.In Part 1 I describe the experimental setup used to investigate electromagnetically induced transparency (EIT).It is shown that impure polarization, stray magnetic fields and imperfect optical alignments cause broadening of the EIT signal and other spurious effects.A systematic approach to minimizing these undesired effects is described, which is shown to produce signals that are four to six times narrower than measurements taken prior to minimization.I conclude part 1 by outlining the progress made toward the production of "slow" light.In Part 2 I describe my earlier research, performed during the first year of my graduate studies, on optical sensing in turbid media.This research culminated in a first accurate measurement of the complex refractive index and in-situ particle sizing in highly scattering opaque media.

Qiang Xu, Zhongyi Guo, Qiangqiang Tao +3 more

In this paper, we have mainly investigated the reconstruction of the polarization states of the incident light which passed through the turbid atmospheric media. Here, a novel polarization retrieve (PR) method is established using a Monte Carlo simulation algorithm, which is proposed to study the influence of particle scattering. The polarization states of the initial field could be retrieved accurately according to the polarization states of the scattered field and the Mueller matrix. In the case of a single homogeneous medium, the mean error of retrieved polarization is close to zero. We have also applied this method to complex atmospheric environments such as random-sized distribution particles and various index of refraction media. By comparison with the existing polarization maintaining method, the results indicate that the PR method is more applicable to disordered media with relatively larger particles. Moreover, the errors of the retrieved degree of polarization are below 0.11%, and the errors of the retrieved angle of polarization are below 0.54% in our mixed media model. So, this work will be very significant for polarizing quantum secure communication in scattering medium over a long-distance scope.

V. N. Lugovoǐ

Vira R. Besaga, Ivan V. Lopushenko, Oleksii Sieryi +3 more

ABSTRACT Polarimetry with quantum light promises improved measurements for various scenarios. However, fundamental understanding of quantum photonic state transport in complex, real media, and tools to interpret the state after interaction with the sample are still lacking. Here, we theoretically and experimentally explore the evolution of polarization‐entangled states in a turbid medium on example of tissue phantoms. By elaborating mathematical relationship between Wolf's coherency matrix and density matrix, we introduce a versatile framework describing the transfer of entangled photons in turbid environments with polarization tracking and resulting quantum state representation with the density operator. Experimentally, we reveal a robust trend in the state evolution depending on the reduced scattering coefficient of the medium. Our theoretical predictions correlate with experimental findings, while the model extends the study by photonic states with different degrees of entanglement. The presented results pave the way for quantitative quantum photonic sensing enabling applications ranging from biomedical diagnostics to remote sensing.