New Pathways Towards the Enhancement of the Image Quality

Stokes parameter imaging of multi-index of refraction biological phantoms utilizing optically active molecular contrast agents

“…Optical imaging provides a detailed description of biological tissues [4,[8][9][10][11][12][13][14][15][16][17][18][19][20], and offers the potential for noninvasive exploration of molecular targets inside the human body. It allows the characterization of a variety of diseases, such as breast cancer, skin cancer, lung cancer and cancer of the bladder; the study of drug effects on the target pathology and drug treatment effects; the development of biomarkers and molecular contrast agents indicative of disease and treatment outcomes; and the analysis of molecular pathways leading to diseases.…”

“…Image formation through detection of the polarization states of light offers distinct advantages for a wide range of detection and classification problems, and has been explored by a number of authors, given the intrinsic potential of optical polarimetry to offer high-contrast, high-specificity images under low-light conditions [4-7, 9, 21, 22]. On the clinical side, optical polarimetry [4,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] provides enhanced imaging and spectral polarimetric information regarding the metabolic information of the tissue, as well as the molecular mechanism of a biological function, drug-cell interaction, single-molecule imaging and so on.…”

“…Based on this assumption, a novel optical imaging technique has been proposed by Giakos [4,[18][19][20]; this technique relies on the synergistic efforts of doping the background surrounding the target with optical active molecules or high index of refraction molecules, in conjunction with the application of efficient polarimetric interrogation techniques. As a result, the proposed technique would provide both optical clearing and enhanced contrast capabilities; minimizing refractive index differences between the optically active fluid medium and the target would result to an increase of the degree of polarization (DOP), with increasing the concentration of the optically active molecules, at the expenses of the contrast resolution; on the other hand, enhanced image contrast would result due to local field enhancement as well as using Stokes parameter imaging because of its intrinsic potential to detect weakly backscattered linearly polarized radiation, in the presence of highly backscattered depolarized radiation, while maintaining the original state of polarization of the incident light.…”

“…As a result, the proposed technique would provide both optical clearing and enhanced contrast capabilities; minimizing refractive index differences between the optically active fluid medium and the target would result to an increase of the degree of polarization (DOP), with increasing the concentration of the optically active molecules, at the expenses of the contrast resolution; on the other hand, enhanced image contrast would result due to local field enhancement as well as using Stokes parameter imaging because of its intrinsic potential to detect weakly backscattered linearly polarized radiation, in the presence of highly backscattered depolarized radiation, while maintaining the original state of polarization of the incident light. Overall, using high refractive index dielectric particles dispersed within fluids would cause the refractive index of the liquid to become a volume-weighted average between refractive indices of optically active molecules and the liquid phase, ultimately giving rise to an amplification of the index of refraction and local field enhancement, yielding an enhanced DOP and DOLP signal-to-background ratio (SBR) [4,[18][19][20].…”