We report the use of axicons to achieve broadband "focus-free" imaging in transmission and reflection at terahertz wavelengths. We demonstrate how the use of a broadband terahertz source improves the resolution of the imaging system, and how by using time-of-flight data the axial position and dimension of objects within the large depth of field of the axicon (160 mm) could be determined.

Magnetic resonance imaging (MRI) allows noninvasive and three-dimensional visualization of whole organisms over time, and, therefore, would be ideally suited to monitor cell trafficking in vivo. Until now, systemically injected cells had been difficult to visualize by MRI because of relatively inefficient labeling methods. We developed a novel, biocompatible, and physiologically inert nanoparti...

Background/Introduction Recent advances in anatomic rendering software have improved our ability to convert image datasets into file formats that can be used to create highly detailed cardiothoracic models. Parallel improvements in 3D printer technology have decreased the time necessary to produce physical representations of these models. We will describe the use of these models to assist with ...

Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational "All Photons Imaging" (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photo...

The purpose of this paper is to study the influence of face expressions on the performance of a 3D face recognition algorithm. Three facial surface matching based algorithms, namely ICP, Localized ICP (LICP) and Region-based ICP (R-ICP), are benchmarked on several sets of data : the two first sets with neutral faces and the last with expressive ones. Results show that the R-ICP algorithm provid...

Medical ultrasound imaging has advanced dramatically since its introduction only a few decades ago. This paper provides a short historical background, and then briefly describes many of the system features and concepts required in a modern commercial ultrasound system. The topics addressed include array beam formation, steering and focusing; array and matrix transducers; echo image formation; t...

Liquid microlenses are attractive for adaptive optics because they offer the potential for both high speed actuation and parallelization into large arrays. Yet, in conventional designs, resonances of the liquid and the complexity of driving mechanisms and/or the device architecture have hampered a successful integration of both aspects. Here we present an array of up to 100 microlenses with syn...

Focusing light through an interface leads to an aberrated intensity distribution that is highly extended with a relatively low peak intensity. We present a method, using a well-chosen annular aperture, that can greatly improve the localization of the intensity about a prescribed point on the axis. Also, the intensity at that point can be increased significantly. By continuously varying the annu...

Optical imaging techniques offer simplistic while highly sensitive modalities for molecular imaging research. In this chapter, the major instrumental necessities for microscopic and whole-animal imaging techniques are introduced. Subsequently, the resulting imaging modalities using visible or near-infrared light are presented and discussed. The aim is to show the current capabilities and applic...

This paper presents the use and characterization of an electrically focus tunable lens to perform axial scanning in a confocal microscope. Lateral and axial resolution are characterized over a >250 µm axial scan range. Confocal microscopy using optical axial scanning is demonstrated in epithelial tissue and compared to traditional stage scanning. By enabling rapid axial scanning, minimizing mot...