Abstract In this work, we solve the problem of modeling generation an acoustic pulse produced by incidence a pulsed laser light upon elastic material. Our concern is about heat transport during absorption electromagnetic radiation. We assume that duration order nanoseconds, and asses if under these conditions contribution in sample essential consideration description phenomena or can ignore it model. begin with energy balance analysis over initial interaction radiation matter context...

We present an experimental analysis of the angular distribution emission a random laser (RL) operating in diffusive regime (∼1% volume fraction scatterers). The RL ensemble was made silica particles suspended 1:1 methanol:water matrix with Rhodamine 6G dye as active medium. found that, for specific pumping-energy-dependent scattering strength, spectrum reached stable features that were angularly preserved. From analysis, we propose this defines novel parametric condition may well be...

We introduce a proof of concept for multimode random laser (RL) emission with fresh whole blood (WB) as the active medium. The experimental principle is adapted from RL using rhodamine 6G (R6G). achieved conditions WB to fluoresce stochastic amplification stimulated radiation. are placed <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi mathvariant="normal">S</mml:mi> mathvariant="normal">i</mml:mi>...

We propose the use of a structured planar mirror as way to obtain physical conditions for which combination an evanescent field and surface plasmon potential would result in atom-trap well located at $\ensuremath{\sim}0.6\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ above mirror's surface. present calculations from we depth slightly bigger than $7\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$. The configuration are single trap, however, there appear be no restrictions extend...

Abstract Background The quantitative interpretation of the radiometric information extracted from infrared (IR) images in individuals with and without type 2 diabetes mellitus (DM2) is an open problem yet to be solved. This particular value given that DM2 a worldwide health onset for evolution toward diabetic foot disease (DFD). Since causes changes at vascular neurological levels, metabolic heat distribution on outer skin modified as consequence such alterations. Of interest this...

We investigate theoretically and experimentally the performance of low-noise capacitive sensors based on polyvinylidene fluoride (PVDF) piezoelectric films to sense water-borne ultrasound signals for their use in photoacoustic tomography. derive a mechanical-to-electrical transfer function capacitor sensor infinite lateral dimensions arbitrary thickness assuming that an wave is normally incident. Then, we analyse response obliquely incident waves large but finite area expression angle...

This study examines one of the open problems yet to solve in photoacoustic tomography: How prepare signals ensure interpretation as projection data? The main part this difficulty is related setting linear transport model. Notably errors are due discrepancy between mathematical reconstruction and physical realization: Tomographic image from projections require a acquisition system. However practice, reality presents different non-linear phenomena. In account incompatibility, it was our...

We investigate the spectral response to ultrasound waves in water of low-noise capacitive sensors based on PVDF polymer piezoelectric films. First, we analyze theoretically mechanical-to-electrical transduction as a function frequency ultrasonic signals and derive an analytic expression sensor's transfer function. Then present experimental results home-made PDVF test from 1 20 MHz induced by commercial hydrophone powered signal generator compare with our theoretical model.

We model theoretically the voltage response to an acoustic pulse of a multilayer system forming low noise capacitive sensor including Polyvinylidene Fluoride piezoelectric film. First we generic detector consisting film between two metallic electrodes that are responsible convert signal into signal. Then calculate pressure-to-voltage transfer function for N-layer piezo-electric capacitor detector, allowing study effects electrode and protective layers thickness in typical layered sensors....

We present an experimental and theoretical method to simultaneously obtain the optical dispersion curves thermal properties of thin film samples. From analytical perspectives, we establish physical conditions validate this novel approach. Similarly, is tested on films aluminium nitride (AlN) deposited quartz crystalline silicon substrates. The set-up that used for open photoacoustic cell pseudo-transmittance spectroscopy (OPC-PATS). sample illuminated with modulated light as a pre-condition...

In this paper we report our preliminary results of the development a computer assisted system for breast biopsy. The is based on tracked ultrasound images breast. A three dimensional volume constructed from set B-scan acquired with calibrated probe. has been designed to assist radiologist during biopsy, and also as training radiology residents. semiautomatic classification algorithm was implemented user annotation tumor an volume. We prototype, tested physical phantom tumor, made polivinil alcohol.

In photoacoustic imaging, the signal attenuation is a well-known source of artifacts over image reconstruction. It recognized that this caused by optical absorption effects and ultrasound broadband scattering. However, sound dispersion generally neglected, although it appears notably in thick or heterogeneous tissues. present Letter, we give an experimental example which both are dealt with as relevant features to be taken into consideration. An analytic perspective these perturbations leads...

We present experimental results related to the manufacturing of phantoms based on polyvinyl-alcohol (PVA) mixedwith SiO2, graphite and Ag nanoparticles. These are dummy representations human tissue thebreast gland. focus our attention representation optical mechanical properties actualbiological healthy that representing a hidden cancer tumor (lesion). The quality samples is testedby ultrasonic imaging laser induced photothermal (PT) detection technique. From former test, mechanicalcontrast...

Abstract We describe new experiments in which the signals induced inside a solid conductor by external excitation using nanosecond long pulsed laser radiation are detected pyro-electric material. From data obtained, it is shown that there previously unreported ‘early’ or ‘fast’ signal propagates at speed greater than reported for sound same media. This observed addition to usually thermal and acoustic waves travel of demonstrate this cannot be adequately accounted existing theories...

Random lasers varying concentration and size of SiO2 scatterers were analyzed. We report on the dependence spectral features (wavelength full width at half maximum) scatterers.

We investigate the spectral response of capacitive sensors with 28 μm thick Polyvinylidene Fluoride (PVDF) films operating in piezoelectric mode. present spectra signals obtained from laser-induced photoacoustic emissions several materials. examine sensor to direct laser pulses and ultrasonic generated by interacting polyvinyl alcohol (PVA) phantoms, neoprene slabs a composite PVA phantom hidden slab neoprene. exhibit sensor's sensitivity thickness, affecting amplitude bandwidth output...

The absorption of modulated or pulsed light leads to non-radiative processes that generate a photoacoustic (PA) wave. standard model assumes the amplitude PA wave is proportional optical absorption. In previous reports we have demonstrated experimentally and theoretically from this proportionality: (1) one can obtain quantitative measurements properties dielectric thin films (2) there may exist relationship between thermal conductivity given sample. Here present analytic results clearly show...