- Photoacoustic and Ultrasonic Imaging
- Optical Imaging and Spectroscopy Techniques
- Thermography and Photoacoustic Techniques
- Random lasers and scattering media
- Optical Coherence Tomography Applications
- Analytical Chemistry and Sensors
- Photonic and Optical Devices
- Nanoplatforms for cancer theranostics
- Ultrasound Imaging and Elastography
- Spectroscopy Techniques in Biomedical and Chemical Research
- Ultrasonics and Acoustic Wave Propagation
- Advanced Fiber Optic Sensors
- Spectroscopy and Laser Applications
- Non-Invasive Vital Sign Monitoring
- Ultrasound and Hyperthermia Applications
- Infrared Thermography in Medicine
- Advanced Fluorescence Microscopy Techniques
- Orbital Angular Momentum in Optics
- Advanced Optical Sensing Technologies
- Optical Polarization and Ellipsometry
- Advanced X-ray and CT Imaging
- Advanced Fiber Laser Technologies
- Advanced Optical Imaging Technologies
- Photodynamic Therapy Research Studies
- Flow Measurement and Analysis
University of Birmingham
2010-2024
University College London
2014-2023
Bellingham Technical College
2015
Mettler-Toledo (Switzerland)
1970
Lymph nodes play a central role in metastatic cancer spread and are key clinical assessment target. Abnormal node vascularization, morphology, size may be indicative of disease but can difficult to visualize with sufficient accuracy using existing imaging modalities. To explore the potential utility photoacoustic for lymph nodes, images ex vivo samples were obtained at multiple wavelengths high-resolution three-dimensional scanner. These showed that hemoglobin based contrast reveals nodal...
Bioluminescence Tomography attempts to quantify 3-dimensional luminophore distributions from surface measurements of the light distribution. The reconstruction problem is typically severely under-determined due number and location measurements, but in certain cases molecules or cells interest form localised clusters, resulting a distribution luminophores that spatially sparse. A Conjugate Gradient-based algorithm using Compressive Sensing was designed take advantage this sparsity, multistage...
A Fabry-Perot ultrasound sensor with nonhygroscopic dielectric mirrors made out of Ta2O5 and SiO2 for use in photoacoustic tomography is described. The offers flat frequency response up to 36 MHz, low noise-equivalent pressure (70 Pa), near-omnidirectional 20 MHz as well optical transparency near-infrared illumination. numerical model was developed predict its response, the results were validated experimentally. An image human palm acquired demonstrate vivo imaging capabilities.
Fabry-Pérot (FP) etalons are used as filters and sensors in a range of optical systems. Often FP illuminated by collimated laser beams, which case the transmitted reflected light fields can be calculated analytically using well established models. However, sometimes more complex beams such focussed Gaussian may also aberrated. Modelling response to these requires sophisticated model. To address this need, we present model that describe an etalon is arbitrary beam. The uses electromagnetic...
A multi-modal optical imaging system for quantitative 3D bioluminescence and functional diffuse is presented, which has no moving parts uses mirrors to provide multi-view tomographic data image reconstruction. It demonstrated that through the use of trans-illuminated spectral near-infrared measurements spectrally constrained reconstruction, recovered concentrations absorbing agents can be used as prior knowledge within visible spectrum. Additionally, first a recently developed surface...
A simple method for measuring the directivity of an ultrasound receiver is described. The makes use a custom-designed laser source which generates large diameter (>1 cm) broadband monopolar plane wave with continuous frequency content extending from ≤330 kHz to ≈80 MHz. highly uniform in amplitude (±5% over >8 mm) and phase (equivalent <;λ/7 at 80 MHz ≥11 mm). To measure directivity, rotated around under test compact centimeter-scale setup. demonstrate method, it was used two small aperture...
Bioluminescence imaging (BLI) is a non-contact, optical technique based on measurement of emitted light due to an internal source, which then often directly related cellular activity.It widely used in pre-clinical small animal studies assess the progression diseases such as cancer, aiding development new treatments and therapies.For many applications, quantitative assessment accurate activity spatial distribution desirable it would enable direct monitoring for prognostic evaluation.This...
Plano-concave optical microresonators (PCMRs) are microcavities formed of one planar and concave mirror separated by a spacer. PCMRs illuminated Gaussian laser beams used as sensors filters in fields including quantum electrodynamics, temperature sensing, photoacoustic imaging. To predict characteristics such the sensitivity PCMRs, model beam propagation through based on ABCD matrix method was developed. validate model, interferometer transfer functions (ITFs) calculated for range were...
Measurement of high acoustic pressures is necessary in order to fully characterize clinical high-intensity focused ultrasound (HIFU) fields, and for accurate validation computational models propagation. However, many existing measurement devices are unable withstand the extreme generated these those that can often exhibit low sensitivity. Here, a planar Fabry-Pérot interferometer with hard dielectric mirrors spacer was designed, fabricated, characterized, its suitability nonlinear fields...
Knowledge of the surface geometry an imaging subject is important in many applications. This information can be obtained via a number different techniques, including time flight imaging, photogrammetry, and fringe projection profilometry. Existing systems may have restrictions on instrument geometry, require expensive optics, or moving parts order to image full subject. An inexpensive generalised profilometry system proposed that account for arbitrarily placed components use mirrors expand...
A novel method is presented for accurately reconstructing a spatially resolved map of diffuse light flux on surface using images the and model imaging system. This achieved by applying model-based reconstruction algorithm with an existing forward propagation through free space that accounts effects perspective, focus, geometry. It shown can be mapped reliably quantitatively very low error, <3% modest signal-to-noise ratio. Simulation shows generalizable to case in which mirrors are used...
A novel straightforward, accessible and efficient approach is presented for performing hyperspectral time-domain diffuse optical spectroscopy to determine the properties of samples accurately using geometry specific models.To allow bulk parameter recovery from measured spectra, a set libraries based on numerical model domain being investigated developed as opposed conventional an analytical semiinfinite slab approximation, which known shown introduce boundary effects.Results demonstrate that...
Fabry-Perot (FP) etalons are used as filters and sensors in a range of optical systems. The reflected transmitted fields associated with an FP etalon have traditionally been predicted by the Airy function, which assumes plane wave illumination. are, however, often illuminated non-collimated beams, rendering function invalid. To address this limitation, we describe angular calculates for arbitrary illumination using spectrum decomposition. Combined realistic models experimental beams...
A numerical model of Gaussian beam propagation in planar Fabry-Perot (FP) etalons is presented. The based on the ABCD transfer matrix method. This method easy to use and interpret, readily connects models lenses, mirrors, fibres other optics aid simulating complex multi-component etalon systems. To validate model, its predictions were verified using a previously validated Fourier optics. demonstrate utility, three different systems simulated. results suggest valid versatile could designing...
Planar glass-etalon Fabry-Pérot (FP) optical ultrasound sensors offer an alternative to piezoelectric for the measurements of high-intensity focused (HIFU) fields and other metrological applications. In this work, a model frequency-dependent directional response FP sensor was developed using global matrix method, treating as multilayered elastic structure. The validated against experimentally measured air-backed cover-slip with well-known material properties. addition, compared...
Steps are presented towards the development of a new bioluminescence tomography (BLT) imaging system for in vivo small animal studies. A 2-mirror-based multi-view data collection scheme is investigated conjunction with multi-spectral imaging, leading to production 3D volumetric maps molecular source distributions simulation and physical phantom studies by way finite element model (FEM) based reconstruction method. proof concept subsequently demonstrated showing full work flow from...
Fabry-Perot (FP) etalons, composed of two parallel mirrors, are used widely as optical filters and sensors. In certain applications, however, such when FP etalons with polymer cavities to detect ultrasound, the mirrors may not be perfectly due manufacturing limitations. As little is known about how being non-parallel impacts upon etalon performance, it challenging optimize design devices. To address this challenge, we developed a model light propagation in etalons. The valid for arbitrary...
Plano-convex optical microresonator detectors have been developed as an alternative to planar Fabry-Pérot (FP) sensors used in all-optical photoacoustic imaging systems with the potential provide two or more orders-of-magnitude higher detection sensitivity. This study further characterises performance of these by investigating their normal incidence frequency response and frequency-dependent directivity. It is shown that thicknesses range ~50-320μm broadband, smooth characteristics low...
An automated, multi-view, spectral bioluminescence tomography system that utilises structured-light-based surface capture techniques along with a model-based approach to image reconstruction is presented. The accuracy of the reconstructed volumetric map light-source distribution within physical phantom demonstrated reference CT scan showing source localisation error 1.7mm.