A5029585257- Photonic and Optical Devices
- Photoacoustic and Ultrasonic Imaging
- Advanced Fiber Laser Technologies
- Semiconductor Lasers and Optical Devices
- Optical Imaging and Spectroscopy Techniques
- Semiconductor Quantum Structures and Devices
- Surgical Simulation and Training
- Anatomy and Medical Technology
- Ultrasound and Hyperthermia Applications
- Thermography and Photoacoustic Techniques
- Advanced Fluorescence Microscopy Techniques
- Functional Brain Connectivity Studies
- Laser-Matter Interactions and Applications
- Ultrasound Imaging and Elastography
- Augmented Reality Applications
- Robotics and Sensor-Based Localization
- Fetal and Pediatric Neurological Disorders
- Advanced X-ray and CT Imaging
- Solid State Laser Technologies
- Machine Learning in Healthcare
- Laser Design and Applications
- Spectroscopy and Laser Applications
- Advanced Neuroimaging Techniques and Applications
- Optical Coherence Tomography Applications
- Muscle activation and electromyography studies
Wellcome / EPSRC Centre for Interventional and Surgical Sciences
2017-2023
University College London
2015-2023
Wellcome Trust
2022
Wellcome Centre for Human Neuroimaging
2019
University of Dundee
2010-2013
Anatomical models are important training and teaching tools in the clinical environment routinely used medical imaging research. Advances segmentation algorithms increased availability of three-dimensional (3D) printers have made it possible to create cost-efficient patient-specific without expert knowledge. We introduce a general workflow that can be convert volumetric data (as generated by Computer Tomography (CT)) 3D printed physical models. This process is broken up into three steps:...
Here we describe methods for creating tissue-mimicking ultrasound phantoms based on patient anatomy using a soft material called gel wax. To recreate acoustically realistic tissue properties, two additives to wax were considered: paraffin increase acoustic attenuation, and solid glass spheres backscattering. The frequency dependence of attenuation was well described with power law over the measured range 3–10 MHz. With addition in concentrations 0 8 w/w%, varied from 0.72 2.91 dB cm−1 at 3...
Tissue-mimicking phantoms are widely used for the calibration, evaluation and standardisation of medical imaging systems, clinical training. For photoacoustic imaging, tissue-mimicking materials (TMMs) that have tuneable optical acoustic properties, high stability, mechanical robustness highly desired. In this study, gel wax is introduced as a TMM satisfies these criteria developing phantoms. The reduced scattering absorption coefficients were independently tuned with addition TiO2 oil-based...
Precise device guidance is important for interventional procedures in many different clinical fields including fetal medicine, regional anesthesia, pain management, and oncology. While ultrasound widely used practice real-time guidance, the image contrast that it provides can be insufficient visualizing tissue structures such as blood vessels, nerves, tumors. This study was centered on development of a photoacoustic imaging system delivered excitation light ranges 750 to 900 nm 1150 1300 nm,...
We report a dual-wavelength passive mode locking regime where picosecond pulses are generated from both ground (lambda = 1263 nm) and excited state transitions 1180 nm), in GaAs-based monolithic two-section quantum-dot laser. Moreover, these results reproduced by numerical simulations which provide better insight on the mode-locked operation.
Acoustic fields with multiple foci have many applications in physical acoustics ranging from particle manipulation to neural modulation. However, the generation of at arbitrary locations three-dimensional is challenging using conventional transducer technology. In this work, optical acoustic focused points a single pulse demonstrated. This achieved optically absorbing surface profiles designed generate specific, user-defined, wavefields. An optimisation approach for design these tailored...
Ultrasound phantoms are invaluable as training tools for vascular access procedures. We developed ultrasound with wall‐less vessels using 3‐dimensional printed chambers. Agar was used a soft tissue–mimicking material, and the were created rods that retracted after agar set. The chambers had integrated luer connectors to allow fluid injections clinical syringes. Several variations on this design presented, which include branched stenotic vessels. results show printing can be well suited...
In this paper, we present the generation of high peak-power picosecond optical pulses in 1.26 μm spectral band from a repetition-rate-tunable quantum-dot external-cavity passively mode-locked laser (QD-ECMLL), amplified by tapered semiconductor amplifier (QD-SOA). The emission wavelength was controlled through chirped volume Bragg grating which used as an external cavity output coupler. An average power 208.2 mW, pulse energy 321 pJ, and peak 30.3 W were achieved. Preliminary nonlinear...
We report on the development of a new generation high-power ultrashort pulse quantum-dot lasers with tapered gain section. Two device designs are proposed and fabricated, different total lengths absorber-to-gain-section length-ratios. These have been informed by numerical simulations dynamic mode-locking regimes their dependence structural parameters. One design demonstrated record-high peak power 17.7 W 1.26 ps width second enabled Fourier-limited 672 fs 3.8 W. A maximum output average 288...
In image-guided laparoscopy, optical tracking is commonly employed, but electromagnetic (EM) systems have been proposed in the literature. this paper, we provide a thorough comparison of EM and for use laparoscopic surgery feasibility study combined, EM-tracked laparoscope ultrasound (LUS) image guidance system.
Accurate and efficient guidance of medical devices to procedural targets lies at the heart interventional procedures. Ultrasound imaging is commonly used for device guidance, but determining location tip can be challenging. Various methods have been proposed track during ultrasound-guided procedures, widespread clinical adoption has remained elusive. With ultrasonic tracking, a determined by communication between ultrasound probe transducer integrated into device. The signal-to-noise ratio...
This paper presents the current status of our research in mode-locked quantum-dot edge-emitting laser diodes, particularly highlighting recent progress spectral and temporal versatility both monolithic external-cavity configurations. Spectral is demonstrated through broadband tunability novel mode-locking regimes that involve distinct bands, such as dual-wavelength mode-locking, robust high-power wavelength bistability. Broad pulse repetition rate also for an laser, revealing a nearly...
Broad Repetition-Rate Tunable Quantum-Dot External-Cavity Passively Mode-Locked Laser with Extremely Narrow Radio Frequency Linewidth, Ying Ding, Maria Ana Cataluna, Daniil Nikitichev, Igor Krestnikov, Livshits, Edik Rafailov
A compact picosecond all-room-temperature orange-to-red tunable laser source in the spectral region between 600 and 627 nm is demonstrated. The radiation obtained by second-harmonic generation a periodically poled potassium titanyl phosphate (PPKTP) multimode waveguide using quantum-dot external-cavity mode-locked laser. maximum output peak power of 3.91 mW at 613 achieved for 85.94 launched pump 1226 nm, resulting conversion efficiency 4.55%.
Optical clearing, in combination with recently developed optical imaging techniques, enables visualization and acquisition of high-resolution, three-dimensional images biological structures deep within the tissue. Many different approaches can be used to reduce light absorption scattering tissue, but there is a paucity research on quantification clearing efficacy. With use custom-made spectroscopy system, we way quantify quality tissue applied it mouse brain. Three techniques were compared:...
Accurate camera and hand-eye calibration are essential to ensure high-quality results in image-guided surgery applications. The process must also be able undertaken by a nonexpert user surgical setting.This work seeks identify suitable method for tracked stereo laparoscope within theater.A custom rig, enable rapid setting, was designed. rig compared against freehand calibration. Stereo reprojection, reconstruction, reconstruction error metrics were used evaluate quality.Use of the reduced...
Broadband wavelength tunability over 136 nm (between 1182.5 and 1319 nm) of picosecond pulses in passive mode-locked regime is demonstrated a multi-section quantum-dot laser external cavity configuration at room temperature. The maximum peak power 870 mW with 15 ps pulse duration was achieved 1226 wavelength.
A broadly tunable master-oscillator power-amplifier (MOPA) picosecond optical pulse source is demonstrated, consisting of an external cavity passively mode-locked laser diode with a tapered semiconductor amplifier. By employing chirped quantum-dot structures on both the oscillator's gain chip and amplifier, wide tunability range between 1187 1283 nm achieved. Under operation, highest output peak power 4.39 W achieved from MOPA, corresponding to spectral density 31.4 dBm/nm.
Accurate identification of tissue structures such as nerves and blood vessels is critically important for interventional procedures nerve blocks. Ultrasound imaging widely used a guidance modality to visualize anatomical in real-time. However, small can be very challenging, accidental intra-neural or intra-vascular injections result significant complications. Multi-spectral photoacoustic provide high sensitivity specificity discriminating hemoglobin- lipid-rich tissues. conventional...
An InAs quantum-dot external-cavity passively modelocked laser with an operation wavelength of 1.27 µm is demonstrated, based on a two-section superluminescent diode bending ridge waveguide and 96% output coupler. Stable modelocking average power up to 60 mW was obtained at repetition frequency 2.4 GHz. This performance corresponds 25 pJ pulse energy directly from the oscillator, which represents 55-fold increase in when compared current state-of-the-art for semiconductor lasers. At 1.14...