Christian Pedersen
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View article: CO2 Sensing Using Symmetrical Three-Wavelength Precompensated Current-Modulated Diode Laser Differential Absorption Lidar
CO2 Sensing Using Symmetrical Three-Wavelength Precompensated Current-Modulated Diode Laser Differential Absorption Lidar Open
In this paper, a novel symmetrical three-wavelength toggling archetype for measuring the concentration of gases using a tunable diode laser differential absorption lidar (DIAL) system is introduced and demonstrated. The system was operated…
View article: CO2 Sensing Using Symmetrical Three-Wavelength Precompensated Current-Modulated Diode Laser Differential Absorption Lidar
CO2 Sensing Using Symmetrical Three-Wavelength Precompensated Current-Modulated Diode Laser Differential Absorption Lidar Open
In this paper, a novel symmetrical three-wavelength toggling archetype for measuring the concentration of gases using a tunable diode laser differential absorption lidar (DIAL) system is introduced and demonstrated. The system was operated…
View article: Benchmarking Precompensated Current-Modulated Diode-Laser-Based Differential Absorption Lidar for CO2 Gas Concentration Measurements at kHz Rate
Benchmarking Precompensated Current-Modulated Diode-Laser-Based Differential Absorption Lidar for CO2 Gas Concentration Measurements at kHz Rate Open
We present a tunable diode-laser absorption spectroscopy (TDLAS) system operating at 1.5711 µm for CO2 gas concentration measurements. The system can operate in either a traditional direct-mode (dTDLAS) sawtooth wavelength scan or a recent…
View article: Low-Cost Hyperspectral Imaging in Macroalgae Monitoring
Low-Cost Hyperspectral Imaging in Macroalgae Monitoring Open
This study presents an approach to macroalgae monitoring using a cost-effective hyperspectral imaging (HSI) system and artificial intelligence (AI). Kelp beds are vital habitats and support nutrient cycling, making ongoing monitoring cruci…
View article: Multi-scale decomposition of sea surface height snapshots using machine learning
Multi-scale decomposition of sea surface height snapshots using machine learning Open
Knowledge of ocean circulation is important for understanding and predicting weather and climate, and managing the blue economy. This circulation can be estimated through Sea Surface Height (SSH) observations, but requires decomposing the …
View article: Long-wavelength, high-resolution microscopy using upconversion in ultra-thin crystals
Long-wavelength, high-resolution microscopy using upconversion in ultra-thin crystals Open
In this paper, a novel approach based on frequency upconversion in ultra-thin nonlinear crystals is investigated for use in high-resolution infrared (IR) microscopy in the 5–12 µm range, an important domain for biomedical research. Traditi…
View article: Remote 3D Imaging and Classification of Pelagic Microorganisms with A Short‐Range Multispectral Confocal LiDAR
Remote 3D Imaging and Classification of Pelagic Microorganisms with A Short‐Range Multispectral Confocal LiDAR Open
Plankton is essential to maintain healthy aquatic ecosystems since it influences the biological carbon pump globally. However, climate change‐induced alterations to oceanic properties threaten planktonic communities. It is therefore crucia…
View article: Integrated-path multi-gas sensor using near-infrared diode lasers: An alternative to vehicle-driven point gas analyzer
Integrated-path multi-gas sensor using near-infrared diode lasers: An alternative to vehicle-driven point gas analyzer Open
Sensors for quantitative monitoring of greenhouse gases from high-emission facilities, such as wastewater treatment and industrial plants, are becoming essential to enforce regulatory compliance in climate action initiatives. A predominant…
View article: Fast horizontal radial plume mapping of N2O using open-path absorption spectroscopy with a quantum-cascade laser
Fast horizontal radial plume mapping of N2O using open-path absorption spectroscopy with a quantum-cascade laser Open
View article: A multi-spectral confocal high-resolution LIDAR for in vivo underwater classification of zooplankton and microplastics
A multi-spectral confocal high-resolution LIDAR for in vivo underwater classification of zooplankton and microplastics Open
View article: Reusability report: Prostate cancer stratification with diverse biologically-informed neural architectures
Reusability report: Prostate cancer stratification with diverse biologically-informed neural architectures Open
In Elmarakeby et al., "Biologically informed deep neural network for prostate cancer discovery", a feedforward neural network with biologically informed, sparse connections (P-NET) was presented to model the state of prostate cancer. We ve…
View article: Reliable coarse-grained turbulent simulations through combined offline learning and neural emulation
Reliable coarse-grained turbulent simulations through combined offline learning and neural emulation Open
Integration of machine learning (ML) models of unresolved dynamics into numerical simulations of fluid dynamics has been demonstrated to improve the accuracy of coarse resolution simulations. However, when trained in a purely offline mode,…
View article: Learnable wavelet neural networks for cosmological inference
Learnable wavelet neural networks for cosmological inference Open
Convolutional neural networks (CNNs) have been shown to both extract more information than the traditional two-point statistics from cosmological fields, and marginalise over astrophysical effects extremely well. However, CNNs require larg…
View article: Confocal LiDAR for remote high-resolution imaging of auto-fluorescence in aquatic media
Confocal LiDAR for remote high-resolution imaging of auto-fluorescence in aquatic media Open
Spatially resolved in situ monitoring of plankton can provide insights on the impacts of climate change on aquatic ecosystems due to their vital role in the biological carbon pump. However, high-resolution underwater imaging is technically…
View article: CW coherent detection lidar for micro-Doppler sensing and raster-scan imaging of drones
CW coherent detection lidar for micro-Doppler sensing and raster-scan imaging of drones Open
We demonstrate a continuous-wave (CW) coherent detection lidar (CDL) capable of detecting micro-Doppler (propeller) signatures and acquiring raster-scan images of small unmanned aerial systems/vehicles (UAS/UAV). The system uses a narrow-l…
View article: A Tunable Hyperspectral Imager for Detection and Quantification of Marine Biofouling on Coated Surfaces
A Tunable Hyperspectral Imager for Detection and Quantification of Marine Biofouling on Coated Surfaces Open
Fouling control coatings (FCCs) are used to prevent the accumulation of marine biofouling on, e.g., ship hulls, which causes increased fuel consumption and the global spread of non-indigenous species. The standards for performance evaluati…
View article: Five decades of terrestrial and freshwater research at Ny-Ålesund, Svalbard
Five decades of terrestrial and freshwater research at Ny-Ålesund, Svalbard Open
For more than five decades, research has been conducted at Ny-Ålesund, in Svalbard, Norway, to understand the structure and functioning of High-Arctic ecosystems and the profound impacts on them of environmental change. Terrestrial, freshw…
View article: Inelastic Confocal LiDAR for localized underwater measurements
Inelastic Confocal LiDAR for localized underwater measurements Open
View article: A silicon source of heralded single photons at 2 <i>μ</i>m
A silicon source of heralded single photons at 2 <i>μ</i>m Open
Mid-infrared integrated quantum photonics is a promising platform for applications in sensing and metrology. However, there are only a few examples of on-chip single-photon sources at these wavelengths. These have limited performances with…
View article: CW Direct Detection Lidar with a Large Dynamic Range of Wind Speed Sensing in a Remote and Spatially Confined Volume
CW Direct Detection Lidar with a Large Dynamic Range of Wind Speed Sensing in a Remote and Spatially Confined Volume Open
A novel continuous-wave (CW) direct detection lidar (DDL) is demonstrated to be capable of wind speed measurement 40 m away with an update rate of 4 Hz using a fiber-based scanning Fabry–Perot interferometer as an optical frequency discrim…
View article: A silicon source of heralded single photons at 2 $μ$m
A silicon source of heralded single photons at 2 $μ$m Open
Mid infrared integrated quantum photonics is a promising platform for applications in sensing and metrology. However, there are only few examples of on-chip single photon sources at these wavelengths. These have limited performances with r…
View article: Non-Destructive Subsurface Inspection of Marine and Protective Coatings Using Near- and Mid-Infrared Optical Coherence Tomography
Non-Destructive Subsurface Inspection of Marine and Protective Coatings Using Near- and Mid-Infrared Optical Coherence Tomography Open
Near- and mid-infrared optical coherence tomography (OCT) is evaluated as a non-destructive and non-contact reflection imaging modality for inspection of industrial and marine coatings. Near-infrared OCT was used to obtain high-resolution …
View article: Dual-band fluorosensor for discriminating non-eating from algae-eating zooplankton in aquatic environments
Dual-band fluorosensor for discriminating non-eating from algae-eating zooplankton in aquatic environments Open
We present a fluorosensor for the detection of laser-induced autofluorescence of zooplankton in marine environments. The sensor uses an inexpensive 410 nm laser diode as excitation source and simultaneously measures two fluorescence bands,…
View article: Carrier lifetime of GeSn measured by spectrally resolved picosecond photoluminescence spectroscopy
Carrier lifetime of GeSn measured by spectrally resolved picosecond photoluminescence spectroscopy Open
We present an experimental setup capable of time-resolved photoluminescence spectroscopy for photon energies in the range of 0.51 to 0.56 eV with an instrument time response of 75 ps. The detection system is based on optical parametric thr…
View article: Mid-IR upconversion imaging: theory and applications
Mid-IR upconversion imaging: theory and applications Open
Upconversion imaging using a χ(2) material can conveniently be viewed as an optical filter known from Fourier optics. First part discusses the solution to Helmholtz Equation with a nonlinear source term representing the χ(2…
View article: Nonlinear crystals for imaging and detection of mid-IR radiation
Nonlinear crystals for imaging and detection of mid-IR radiation Open
The mid-IR wavelength range, i.e. 2-25 μm, houses the vibrational spectra of most gasses and large molecules found in complex structures such as tissue, plastics or food. When designing an upconversion system for imaging or mid-IR detectio…
View article: Moisture performance of a new thermal insulation composite for interior application
Moisture performance of a new thermal insulation composite for interior application Open
The paper introduces prototypes of a new composite insulation product for interior application. The product consists of a standard mineral fibre insulation batt, which is wrapped in a combination of a thin fabric of moisture absorbing, cap…
View article: A field study of the individual and combined effect of ventilation rate and lighting conditions on pupils’ performance
A field study of the individual and combined effect of ventilation rate and lighting conditions on pupils’ performance Open
View article: Parametric upconversion imaging and its applications
Parametric upconversion imaging and its applications Open
This paper provides an extensive survey of nonlinear parametric upconversion infrared (IR) imaging, from its origin to date. Upconversion imaging is a successful innovative technique for IR imaging in terms of sensitivity, speed, and noise…
View article: Mid-infrared upconversion imaging using femtosecond pulses
Mid-infrared upconversion imaging using femtosecond pulses Open
Mid-infrared (mid-IR) imaging and spectroscopic techniques have been rapidly evolving in recent years, primarily due to a multitude of applications within diverse fields such as biomedical imaging, chemical sensing, and food quality inspec…