Time-gated transillumination of objects in highly scattering mediausing a subpicosecond optical amplifier

We have developed an optical system that simultaneously selects and amplifies photons in a time window of less than 10 ps. This new subpicosecond optical amplifier allowed us to realize one-dimensional images of a striped pattern with a spatial resolution of 200-μm through a 30-mm liquid scattering medium. Monte Carlo simulations were performed to study the relative importance of parameters characterizing the medium and the time-gated amplifying system in relation to the image sharpness. The potential application of this system in medical imaging is discussed     

Numerical analysis of electromagnetic scattering from 3D dielectric objects using the Yasuura method

In order to calculate 3D electromagnetic scattering problems by dielectric objects which we need to solve a large‐size simultaneous linear equation, we present a rapid algorithm on the Yasuura method where we accelerate the convergence rate of solution by using an array of multipoles as well as a conventional multipole. As a result, we can obtain the radar cross sections of dielectric objects in the optical wave region over a relatively wide frequency range and a TDG pulse response. Furtherrmore, we analyze the scattering data about dielectric objects by using the pulse responses cut by an appropriate window function in the time domain and clarify the scattering processes on dielectric objects. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(2): 39–45, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ eej.10292     

Measurement of the axial point spread function in scattering media using single-mode fiber-based optical coherence tomography

The authors studied the axial point spread function of optical coherence tomography for Gaussian intensity profiles emitted from and coupled back into single-mode fibers for signals from a scattering medium. The determined Rayleigh length of the axial point spread function was roughly twice the one measured from the reflection of a mirror. Using the measured point spread function in combination with the single backscatter model allowed determination of the attenuation coefficient of the suspension.     

Halftone spatial frequency domain imaging enables kilohertz high-speed label-free non-contact quantitative mapping of optical properties for strongly turbid media

The ability to quantify optical properties (i.e., absorption and scattering) of strongly turbid media has major implications on the characterization of biologic...