No abstract

The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

In this study, for the first time, a Photoacoustic Microscopy instrument driven by a single optical source operating over a wide spectral range (475–2400 nm), covering slightly more than two octaves is demonstrated. Xenopus laevis tadpoles were imaged in vivo using the whole spectral range of 2000 nm of a supercontinuum optical source, and a novel technique of mapping absorbers is also demonstrated, based on the supposition that only one chromophore contributes to the photoacoustic signal of each individual voxel in the 3D photoacoustic image. By using a narrow spectral window (of 25 nm bandwidth) within the broad spectrum of the supercontinuum source at a time, in vivo hyper-spectral Photoacoustic images of tadpoles are obtained. By post-processing pairs of images obtained using different spectral windows, maps of five endogenous contrast agents (hemoglobin, melanin, collagen, glucose and lipids) are produced.

. Conventional optoacoustic microscopy (OAM) instruments have at their core a nanosecond pulse duration laser. If lasers with a shorter pulse duration are used, broader, higher frequency ultrasound waves are expected to be generated and as a result, the axial resolution of the instrument is improved. Here, we exploit the advantage offered by a picosecond duration pulse laser to enhance the axial resolution of an OAM instrument. In comparison to an instrument equipped with a 2-ns pulse duration laser, an improvement in the axial resolution of 50% is experimentally demonstrated by using excitation pulses of only 85 ps. To illustrate the capability of the instrument to generate high-quality optoacoustic images, en-face , in-vivo images of the brain of Xenopus laevis tadpole are presented with a lateral resolution of throughout the entire axial imaging range.

The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

No abstract

Robust, non-destructive testing imaging instruments, capable to provide valuable information from within the body of materials is important for both quality control and the development of new materials, for industrial and medical applications. Conventional non-destructive testing (NDT) methods, such as radiographic or ultrasound-based techniques, allow for deep axial range imaging, however, they are either using non-safe radiation or/and exhibit low imaging resolutions. The speed at which the standard NDT methods deliver images is also limited. The development of photoacoustic (PA) and optical coherence tomography (OCT) applications in the field of NDT have grown exponentially over the past years, offering faster, higher resolution images. Both techniques, PA and OCT bring a plethora of benefits to the current methods. However, a multitude of challenges still needs to be addressed to truly make either of them the technique of choice for NDT applications. In this manuscript, a short overview of the challenges that these two imaging techniques are facing when used for NDT applications is presented. Illustrative high-resolution images, produced by a dual PA/OCT imaging instrument developed within the Applied Optics Group at the University of Kent are presented. These images demonstrate unique capabilities for NDT applications.

No abstract