Florian Schepers
A5004134892- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Photonic and Optical Devices
- Dark Matter and Cosmic Phenomena
- Orbital Angular Momentum in Optics
- Advanced Fiber Optic Sensors
- Cosmology and Gravitation Theories
- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Particle physics theoretical and experimental studies
- Silicon Nanostructures and Photoluminescence
- Geophysics and Sensor Technology
- Semiconductor Lasers and Optical Devices
- Neutrino Physics Research
- Solid State Laser Technologies
- Photorefractive and Nonlinear Optics
- Mechanical and Optical Resonators
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Color Science and Applications
- Photonic Crystal and Fiber Optics
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
- Radiation Therapy and Dosimetry
- Advanced Photonic Communication Systems
University of Münster
2016-2023
Queen's University
2017-2023
University of Sussex
2018
DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg LAr contained in spherical acrylic vessel. This paper reports on the analysis $758\text{ }\text{ }\mathrm{tonne}\ifmmode\cdot\else\textperiodcentered\fi{}\mathrm{day}$ exposure taken over period 231 live-days during first year operation. No candidate signal events are observed WIMP-search region interest, which...
We demonstrate supercontinuum generation in stoichiometric silicon nitride (Si3N4 SiO2) integrated optical waveguides, pumped at telecommunication wavelengths. The pump laser is a mode-locked erbium fiber wavelength of 1.56 µm with pulse duration 120 fs. With waveguide-internal energy 1.4 nJ and waveguide 1.0 × 0.9 cross section, designed for anomalous dispersion across the 1500 nm range, output spectrum extends from visible, around 526 nm, up to mid-infrared, least 2.6 µm, instrumental...
This Letter reports the first results of a direct dark matter search with DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing large target mass, LAr contained in spherical acrylic vessel 3600 kg capacity. is viewed by an array PMTs, which would register scintillation light produced rare nuclear recoil signals induced particle scattering. An analysis 4.44 live days (fiducial exposure 9.87 ton day) data taken...
Abstract The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. largest background comes $$^{39}\text{ Ar }$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow/> <mml:mn>39</mml:mn> </mml:msup> <mml:mspace/> <mml:mtext>Ar</mml:mtext> </mml:mrow> </mml:math> beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator:...
Abstract The specific activity of the $$\beta $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>β</mml:mi> </mml:math> decay $$^{39}$$ <mml:msup> <mml:mrow /> <mml:mn>39</mml:mn> </mml:msup> Ar in atmospheric argon is measured using DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total (3269 ± 24) kg liquid distilled from atmosphere to search for dark matter. This detector well-suited measure owing its very low background levels. achieved two...
DEAP-3600 uses liquid argon contained in a spherical acrylic vessel as target medium to perform sensitive spin-independent dark matter search. Argon scintillates the vacuum ultraviolet spectrum, which requires wavelength shifting convert VUV photons visible so they can be transmitted through light guides and detected by surrounding photomultiplier tubes. The shifter 1,1,4,4-tetraphenyl-1,3-butadiene was evaporatively deposited inner surface of under vacuum. Two evaporations were performed on...
Abstract Transverse mode-locking in an end-pumped solid state laser by amplitude modulation with acousto-optic modulator was investigated. Using the stochastic parallel gradient descent algorithm modal power coefficients and phases of transverse mode-locked (TML) beam were reconstructed from measured spatial spatio-temporal intensity distributions, respectively. The distribution revealed that average mode order process could be increased a factor about 8 compared to previous works,...
The specific activity of the beta decay $^{39}$Ar in atmospheric argon is measured using DEAP-3600 detector. DEAP-3600, located 2 km underground at SNOLAB, uses a total (3269 $\pm$ 24) kg liquid distilled from atmosphere to search for dark matter. This detector with very low background pulseshape discrimination differentiate between nuclear recoils and electron well-suited measure $^{39}$Ar. With 167 live-days data, time extraction [0.964 0.001 (stat) 0.024 (sys)] Bq/kg$_{\rm atmAr}$ which...
Abstract The conversion of transverse mode-locked (TML) laser beams from a Hermite-Gaussian (HG) to Laguerre-Gaussian (LG) mode set using cylindrical lens converter was demonstrated experimentally. By changing the spatial symmetry new spatio-temporal dynamics for TML lasers were enabled. In particular, fast linear motion an oscillating spot, generated by based on HG modes, translated into circular beam LG modes. successfully different average orders. Apart ellipticity about $$6\%$$ <mml:math...
A longitudinal mode-locked state can be converted to a transverse by exploiting the spectral and spatial filtering of an empty optical resonator. Carrier amplitude modulation sidebands were simultaneously transmitted conversion resonator, yielding phase-locked superpositions up five modes. Equivalently, amplitude-modulated beam was into that periodically moved across plane. Precise control over shape during oscillation gained independently altering set modes their respective powers, which...
We demonstrate the generation of ultra-broadband supercontinua in Si3N4 waveguides at a pump wavelength 1560nm. The supercontinuum extends to beyond 2.6 µm infrared and has spectral width more then 453THz.
A longitudinal mode-locked state can be converted to a transverse by exploiting the spectral and spatial filtering of an empty optical resonator. Carrier amplitude modulation sidebands were simultaneously transmitted conversion resonator, yielding phase-locked superpositions up five modes. Equivalently, amplitude-modulated beam was into that periodically moved across plane. Precise control over shape during oscillation gained independently altering set modes their respective powers, which...
Optical resonators are routinely used as optical spectrum analyzers or mode-cleaners [1], [2]. However, shown in this work, their spectral and spatial filtering properties can also be utilized to convert longitudinal transverse mode-locked states vice versa. For conversion the components of an incident beam matched mode resonances empty cavity. As a result, all transmitted simultaneously converted into modes. Thus, amplitude-modulated, i.e. mode-locked, is that rapidly oscillates across...
This paper presents methods for the characterization of monochrome or colour imaging sensors using multiple narrowband LED as radiance sources and optimization algorithms in order to estimate their spectral responsivity. method can be used cases where a monochromator setup is not available fast needed. In addition, XYZ coordinates various are estimated camera counts from three channels (RGB). For this purpose, linear non-linear models RGB values tested. The trained different groups reference...
We present the beam pointing detection of a fundamental mode by superposition with frequency-shifted higher-order Hermite-Gaussian and experimentally demonstrate its applicability for stabilization position. © 2019 The Author(s)
We present cavity-external spatial gain shaping based on a digital micromirror device for the selective and realignment-free excitation of nearly 1000 different single Hermite-Gaussian modes in an end-pumped Nd:YVO 4 . © 2019 The Author(s)
Summary form only given. The excitation of transverse laser modes, can be achieved by a cavity-internal amplitude or phase modulation the light. For this purpose typically additional components are applied, which result in increased losses and limited resonator internal power [1]. Therefore, gain shaping based methods [2], where selective mode is via cavity-external pump beam great interest, as they require no modification cavity itself. However, so far presented strongly with respect to...
The detection and stabilization of laser beam pointing is great interest for multiple high precision applications, e.g., interferometric measurements [1]. Beside the typically applied based on quadrant photodiodes [2] an alternative method superposition deflected with a higher order mode has been demonstrated [3]. However, in so far presented approach was realized by two modes at same frequency homodyne setup, requiring detectors. Here, we present that tilt displacement can also be...