Robert H. Hadfield
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In Vivo Assessment of Benzoporphyrin Uptake and Singlet Oxygen Generation in Mice for Photodynamic Therapy Monitoring Open
The efficacy of photodynamic therapy (PDT) is strongly influenced by the biodistribution of the photosensitizer and the local generation of 1O2 within tumor tissue. However, real-time in vivo monitoring of these critical parameters for cli…
Mid-infrared superconducting nanowire single-photon detectors: Potential, progress, and challenges Open
The ability to detect single photons in the mid-infrared spectral range (beyond 2 μm wavelength, photon energy below 0.62 eV) is the key to unlocking a range of emerging scientific applications, from remote sensing LIDAR, molecular spectro…
Comparison of multispectral singlet oxygen luminescence dosimetry and singlet oxygen explicit dosimetry in artificial phantom Open
We demonstrate that singlet oxygen ( ) detected through MSOLD can reliably quantify ROS concentrations in BPD-mediated PDT with accuracy comparable to the SOED model, which requires separate measurements of light fluence rate, photosensiti…
View article: Transmission electron microscopy analysis of atomic layer deposited NbTiN/NbN superconducting thin films
Transmission electron microscopy analysis of atomic layer deposited NbTiN/NbN superconducting thin films Open
Atomic-scale processing and precise control of superconducting thin films are essential for the advancement and large-scale implementation of superconducting quantum technologies. Consequently, detailed analysis of the structural features …
Superconducting Quantum Sensors for Fundamental Physics Searches Open
Superconducting Transition Edge Sensors (TESs) are a promising technology for fundamental physics applications due to their low dark count rates, excellent energy resolution, and high detection efficiency. On the DESY campus, we have been …
View article: Mid-infrared high-resolution photon-counting LiDAR
Mid-infrared high-resolution photon-counting LiDAR Open
Mid-infrared (MIR) detection at the single-photon limit has become increasingly accessible, enabling applications in free-space communications, industrial sensing, astronomy, and biomedicine. However, direct time-correlated single photon-c…
Engineering high-Q superconducting tantalum microwave coplanar waveguide resonators for compact coherent quantum circuit Open
Tantalum (Ta) has recently received considerable attention in manufacturing robust superconducting quantum circuits. Ta offers low microwave loss, high kinetic inductance compared to aluminium (Al) and niobium (Nb), and good compatibility …
Waveguide integrated superconducting nanowire single-photon detectors for integrated photonics Open
Integrated photonics is expected to play a key role in the scalability of quantum systems for applications such as quantum computing, quantum communications, quantum internet, and quantum metrology. One of the primary components of quantum…
View article: Superconducting Nb<i>x</i>Ti1−<i>x</i>N prepared at high deposition rates with plasma-enhanced atomic layer deposition and substrate biasing
Superconducting Nb<i>x</i>Ti1−<i>x</i>N prepared at high deposition rates with plasma-enhanced atomic layer deposition and substrate biasing Open
Superconducting films ranging from a few to hundreds of nanometers thickness are integral to a wide range of quantum devices. The further development of quantum technologies hinges on material advances. With its atomic-scale growth control…
Analysis of Singlet Oxygen Luminescence Generated By Protoporphyrin IX Open
The effectiveness of photodynamic therapy (PDT) for cancer treatment relies on the generation of cytotoxic singlet oxygen (1O2) in type II PDT. Hence, monitoring of 1O2 generation during PDT enables optimal treatment delivery to the tumor …
View article: High-resolution long-distance depth imaging LiDAR with ultra-low timing jitter superconducting nanowire single-photon detectors
High-resolution long-distance depth imaging LiDAR with ultra-low timing jitter superconducting nanowire single-photon detectors Open
Single-photon time-of-flight light detection and ranging (LiDAR) is a versatile technique for the measurement of absolute distances and for depth profiling. It has a wide variety of applications (e.g., land surveying, autonomous car naviga…
View article: Plasma Processes for Vertical Niobium Nitride Superconducting Through Silicon Vias
Plasma Processes for Vertical Niobium Nitride Superconducting Through Silicon Vias Open
Superconducting through silicon vias are emerging as a key interconnect technology to realise a scalable superconducting quantum computing platform. Integration of semiconductor technology into quantum devices is becoming more common whils…
Engineering high-Q superconducting tantalum microwave coplanar waveguide resonators for compact coherent quantum circuits Open
Tantalum (Ta) has recently received considerable attention in manufacturing robust superconducting quantum circuits. Ta offers low microwave loss, high kinetic inductance compared to aluminium (Al) and niobium (Nb), and good compatibility …
Correction of Multispectral Singlet Oxygen Luminescent Dosimetry (MSOLD) for Tissue Optical Properties in Photofrin-Mediated Photodynamic Therapy Open
The direct detection of singlet-state oxygen (1O2) constitutes the holy grail dosimetric method for type-II photodynamic therapy (PDT), a goal that can be quantified using multispectral singlet oxygen near-infrared luminescence dosimetry (…
Correction of Multispectral Singlet Oxygen Luminescent Dosimetry (MSOLD) for Tissue Optical Properties in Photofrin-Mediated Photodynamic Therapy Open
Direct detection of singlet-state oxygen (1O2) constitutes the holy grail dosimetric method for type-II photodynamic therapy (PDT), a goal that can be quantified using multispectral singlet oxygen near-infrared luminescence dosimetry (MSOL…
Mid-infrared characterization of NbTiN superconducting nanowire single-photon detectors on silicon-on-insulator Open
Superconducting nanowire single-photon detectors are widely used for detecting individual photons across various wavelengths from ultraviolet to near-infrared range. Recently, there has been increasing interest in enhancing their sensitivi…
Photon counting for axion interferometry Open
Axions and axionlike particles are well-motivated dark matter candidates. We propose a novel experiment that uses single-photon detection interferometry to search for axions and axionlike particles in the Galactic halo. We show that photon…
Optimal Leveraging of a Gifford-McMahon Cryocooler’s Regenerative Cooling Power for SNSPD Applications Open
Superconducting nanowire single photon detectors (SNSPDs) offer unparalleled efficiency, minimal dark count rates, and picosecond jitter, making them ideal for single photon detector applications across the visible to mid-IR spectrum. A co…
Multispectral singlet oxygen luminescent dosimetry (MSOLD) for Photofrin-mediated PDT Open
Multispectral singlet oxygen dosimetry (MSOLD) provides a mean for direct detection of singlet oxygen, responsible for tumor kill for type II PDT. An InGaAs spectrometer or an InGaAs detector coupled with to narrow beam filters (1200, 1240…
View article: Technology development for a low-mass solar system and interstellar communications system
Technology development for a low-mass solar system and interstellar communications system Open
We describe the requirements and associated technology development plan for the communications data link from low mass interstellar probes. This work is motivated by several proposed deep space and interstellar missions with an emphasis on…
View article: High-uniformity atomic layer deposition of superconducting niobium nitride thin films for quantum photonic integration
High-uniformity atomic layer deposition of superconducting niobium nitride thin films for quantum photonic integration Open
Atomic layer deposition (ALD) has been identified as a promising growth method for high-uniformity superconducting thin films for superconducting quantum photonic applications, offering superior uniformity, thickness control and conformali…
View article: Ultrathin superconducting TaCxN1−x films prepared by plasma-enhanced atomic layer deposition with ion-energy control
Ultrathin superconducting TaCxN1−x films prepared by plasma-enhanced atomic layer deposition with ion-energy control Open
This work demonstrates that plasma-enhanced atomic layer deposition (PEALD) with substrate biasing enables the preparation of ultrathin superconducting TaCxN1−x films. By comparing with films grown without substrate biasing, the enhanced i…
Single-photon detection for long-range imaging and sensing Open
Single-photon detectors with picosecond timing resolution have advanced rapidly in the past decade. This has spurred progress in time-correlated single-photon counting applications, from quantum optics to life sciences and remote sensing. …
Brain-inspired nanophotonic spike computing: challenges and prospects Open
Nanophotonic spiking neural networks (SNNs) based on neuron-like excitable subwavelength (submicrometre) devices are of key importance for realizing brain-inspired, power-efficient artificial intelligence (AI) systems with high degree of p…
Characterizing Niobium Nitride Superconducting Microwave Coplanar Waveguide Resonator Array for Circuit Quantum Electrodynamics in Extreme Conditions Open
The high critical magnetic field and relatively high critical temperature of niobium nitride (NbN) make it a promising material candidate for applications in superconducting quantum technology. However, NbN-based devices and circuits are s…
Multispectral Singlet Oxygen Luminescent Dosimetry (MSOLD) for PHOTOFRIN-mediated photodynamic therapy Open
Direct detection of singlet-state oxygen ([1O2]) constitutes the holy grail dosimetric method for type II PDT, a goal that can be quantified using multispectral singlet oxygen dosimetry (MSOLD). However, the short lifetime and extremely we…
Two-dimensional cuprate nanodetector with single telecom photon sensitivity at T = 20 K Open
Detecting light at the single-photon level is one of the pillars of emergent photonic technologies. This is realized through state-of-the-art superconducting detectors that offer efficient, broadband and fast response. However, the use of …
View article: Mid-infrared timing jitter of superconducting nanowire single-photon detectors
Mid-infrared timing jitter of superconducting nanowire single-photon detectors Open
Detector timing jitter is a key parameter in advanced photon counting applications. Superconducting nanowire single-photon detectors offer the fastest timing jitter in the visible to telecom wavelength range and have demonstrated single-ph…