Absorption-Induced Image Resolution Enhancement in Scattering Media

Abstract

Highly scattering media pose significant challenges for many optical imaging applications due to the loss of information inherent to the scattering process. Absorption can also result in significant degradation of image quality. However, absorption can actually improve the resolution of images transmitted through scattering media in certain cases. Here we study how the presence of absorption can enhance the quality of an image transmitted through a scattering medium, by investigating the dependence of this enhancement on the medium's scattering properties. We find that absorptioninduced image resolution enhancement is substantially larger for media consisting of isotropic scatterers (e.g., dielectric nanoparticles) than for strongly forward-scattering media (e.g., biological tissue). This work leads to a broader understanding, and ultimately control, of the optical properties of strongly absorbing, scattering media.

Absorption by water increases fluorescence image contrast of biological tissue in the shortwave infrared

“…We observe, in these experiments, that image contrast increases with increasing water absorption, and that contrast is the greatest at around 1,450 nm where absorption from water is the greatest. The idea that absorption can aid image contrast in a scattering medium (e.g., tissue) has been previously demonstrated; the underlying principle is that absorption preferentially suppresses photons having a longer path length through tissue (e.g., multiply scattered photons and fluorescence from deep background structures) which contribute to noise, over ballistic photons which form the image (35)(36)(37)44). These prior studies administered exogenous agents to the sample to improve image contrast in the visible and NIR, whereas we show that the inherent optical properties of tissue in the SWIR provide sufficient variation in absorption to significantly affect image contrast without the need for an exogenous agent.…”

Balancing Near-Field Enhancement, Absorption, and Scattering for Effective Antenna–Reactor Plasmonic Photocatalysis

“…Furthermore, while it is relatively straightforward to conclude that localizing a plasmonic particle near a non-plasmonic catalytic particle will enhance light absorption in the non-plasmonic particle, it is not clear how this translates to enhanced photocatalysis in the light-limited regime, where all photons must be utilized in a 3-D packed bed of catalytic particles. Optimizing photocatalytic complexes for highest efficiency photon management in the light-limited regime is of critical importance for further development of this approach.In the work reported here, a series of antenna-reactor complexes consisting of core@shell/satellite (Ag@SiO 2 /Pt) heterostructures with varying Ag core diameter (12,25,50 and 100 nm) were synthesized and their photocatalytic properties for the kinetically well-defined CO oxidation reaction were quantitatively compared. Rigorous quantum yield measurements in the light-limited regime demonstrate that for heterostructures with Ag nanoparticles (Ag NPs) in an intermediate size range of 25 and 50 nm diameter, plasmon-enhanced photocatalytic performance was observed at rates more than four times larger than for either smaller (12 nm diameter) or larger (100 nm diameter) Ag particles.…”

“…In the work reported here, a series of antenna-reactor complexes consisting of core@shell/satellite (Ag@SiO 2 /Pt) heterostructures with varying Ag core diameter (12,25,50 and 100 nm) were synthesized and their photocatalytic properties for the kinetically well-defined CO oxidation reaction were quantitatively compared. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 6 catalyst bed, where each heterostructure behaves locally both as an absorber and a scatterer of the incident light.…”

Broad-Band Transmission Characteristics of Polarizations in Foggy Environments

“…As depicted in Figure 5b, with an increasing transmission length, there is a large absorption effect at these special wavelengths (2.8 µm, 6.2 µm, and 12.0 µm), and the normalized intensity power is already below 20% when the transmission length is larger than 3000 m for these high-absorption wavelengths. However, the multiple-scattered photons have a longer path through scattering systems, and when high absorption is present, multiple-scattered photons are easier to be absorbed [28,29]. As such, these photons that can reach the detector are mainly high-fidelity ballistic photons.…”