A5002746716- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Diamond and Carbon-based Materials Research
- Optical Coatings and Gratings
- Photonic and Optical Devices
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Advanced Surface Polishing Techniques
- Advanced Fiber Laser Technologies
- Astro and Planetary Science
- Surface Modification and Superhydrophobicity
- Lubricants and Their Additives
- Analytical Chemistry and Sensors
- Adhesion, Friction, and Surface Interactions
- Laser Material Processing Techniques
- Spectroscopy and Laser Applications
- Mechanical stress and fatigue analysis
- Metal and Thin Film Mechanics
- Advanced Fiber Optic Sensors
- Advanced Semiconductor Detectors and Materials
- Fluid Dynamics and Heat Transfer
- Photonic Crystals and Applications
- Semiconductor Lasers and Optical Devices
- Tribology and Wear Analysis
- Calibration and Measurement Techniques
Uppsala University
2014-2024
University of South Australia
2009-2014
For incorporating superhydrophobic surfaces in microfluidic systems, it is important to understand the ability of state withstand hydraulic pressure. In this paper we describe experiments probe collapse transition on completely covered by water, where air film formed surface closed. Polyethylene foils nanoimprinted with micrometre sized pillars different geometries and densities are used as model surfaces. The pressure required for from Cassie Wenzel measured all also compared analytical...
The wettability of surfaces microstructured with square pillars was studied, where the static advancing contact angle on planar surface 72 degrees. We observed elevated angles (up to 140 degrees) these structures for droplets in Wenzel state. No air trapped structured beneath liquid, ruling out well-known Lotus leaf effect. Instead, we show that apparent hydrophobicity is related line pinning at pillar edges, giving a strong dependence wetting hysteresis fraction pinned pillars. Simulating...
ABSTRACT Combination therapy is recommended for infections with carbapenemase-producing Klebsiella pneumoniae . However, limited data exist on which antibiotic combinations are the most effective. The aim of this study was to find effective against metallo-beta-lactamase-producing K. (MBL-KP). Two VIM- and two NDM-producing strains, all susceptible colistin, were exposed antibiotics at clinically relevant static concentrations during 24-h time-kill experiments. Double- triple-antibiotic...
Uncovering the ingredients and architecture of planetary systems is a very active field research that has fuelled many new theories on giant planet formation, migration, composition, interaction with circumstellar environment. We aim at discovering studying such systems, to further expand our knowledge how low-mass companions form evolve. obtained high-contrast H-band images environment F5V star HD206893, known host debris disc never detected in scattered light. These observations are part...
Abstract We present L ’-band imaging of the PDS 70 planetary system with Keck/NIRC2 using new infrared pyramid wave front sensor. detected both b and c in our images, as well rim circumstellar disk. After subtracting off a model disk, we measured astrometry photometry planets. Placing priors based on dynamics system, estimated to have semimajor axis <?CDATA ${20}_{-4}^{+3}$?> au ${34}_{-6}^{+12}$?> (95% credible interval). fit spectral energy distribution (SED) For b, were able place better...
ABSTRACT An optical vortex coronagraph has been implemented within the NIRC2 camera on Keck II telescope and used to carry out on-sky tests observations. The development of this new L ′-band observational mode is described, an initial demonstration capability presented: a resolved image low-mass companion HIP 79124, which had previously detected by means interferometry. With 79124 B at projected separation 186.5 mas, both small inner working angle related imaging improvements were crucial in...
Giant exoplanets on wide orbits have been directly imaged around young stars. If the thermal background in mid-infrared can be mitigated, then with lower masses also imaged. Here we present a ground-based observing approach that enables imaging low-mass temperate nearby stars, and particular within closest stellar system, α Centauri. Based 75-80% of best quality images from 100 h cumulative observations, demonstrate sensitivity to warm sub-Neptune-sized planets throughout much habitable zone...
Coronagraphy is a powerful technique to achieve high contrast imaging and hence image faint companions around bright targets. Various concepts have been used in the visible near-infrared regimes, while coronagraphic applications mid-infrared remain nowadays largely unexplored. Vector vortex phase masks based on concentric subwavelength gratings show great promise for such applications. We aim at producing validating first high-performance broadband focal plane mask coronagraphs regime,...
Context. High contrast imaging has thoroughly combed through the limited search space accessible with first-generation ground-based adaptive optics instruments and Hubble Space Telescope. Only a few objects were discovered, many non-detections reported statistically interpreted. The field is now in need of technological breakthrough. Aim. Our aim to open new systems such as NACO at Very Large Telescope, by providing ground-breaking inner working angle (IWA) capabilities L' band. band sweet...
Pinning and wicking of a liquid meniscus in square array pillars is investigated numerical energy minimizations compared to wetting experiments.
The hydrophobicity of microtextured diamond surfaces was investigated. Pillarlike structures were fabricated in both nanocrystalline and microcrystalline diamond. By changing the surface termination textured surface, we could switch between superhydrophobic hydrophilic surfaces. Examined terminations hydrogen, fluorine, oxygen. To evaluate wetting properties, advancing receding contact angles measured. designing pillars with a wide top on narrower silicon stem, superhydrophobicity achieved...
The first combination of mid-infrared (MIR) tunable quantum cascade lasers (tQCLs) with thin-film diamond strip waveguides (DSWGs) suitable for advanced chemical sensing/biosensing is demonstrated. sensing system composed thin films grown on surface-passivated Si wafers via vapor deposition (CVD) and microstructured using inductively coupled plasma (ICP) etching, serving as photonic radiation emitted by a broadly laser (tQCL) in the spectral regime 5.78–6.35 μm (1570–1730 cm–1)....
HD 141569 A is a pre-main sequence B9.5 Ve star surrounded by prominent and complex circumstellar disk, likely still in transition stage from protoplanetary to debris disk phase. Here, we present new image of the third inner component made L' band (3.8 micron) during commissioning vector vortex coronagraph recently installed near-infrared imager spectrograph NIRC2 behind W.M. Keck Observatory II adaptive optics system. We used reference point spread function subtraction, which reveals...
In this paper, we present a solution for creating robust monolithic achromatic half-wave plates (HWPs) the infrared, based on form birefringence of subwavelength gratings (SWGs) made out diamond. We use rigorous coupled wave analysis to design gratings. Our shows that diamond, besides its outstanding physical and mechanical properties, is suitable substrate manufacture mid-infrared HWPs, thanks high refractive index, which allows etching SWGs with lower aspect ratio. Based our optimized...
We present the first observations obtained with L'-band AGPM vortex coronagraph recently installed on LBTI/LMIRCam. The (Annular Groove Phase Mask) is a vector made from diamond subwavelength gratings. It designed to improve sensitivity and dynamic range of high-resolution imaging at very small inner working angles, down 0.09 arcseconds in case LBTI/LMIRCam L' band. During hours sky, we observed young A5V star HR8799 goal demonstrate performance assess its relevance for ongoing LBTI planet...
Context. The Annular Groove Phase Mask (AGPM) is one possible implementation of the vector vortex coronagraph, where helical phase ramp produced by a concentric subwavelength grating. For several years, we have been manufacturing AGPMs etching gratings into synthetic diamond substrates using inductively coupled plasma etching. Aims. We aim to design, fabricate, optimize, and evaluate new L-band that reach highest coronagraphic performance, for applications in current forthcoming infrared...
Control of the sidewall angle diamond microstructures was achieved by varying gas mixture, bias power and mask shape during inductively coupled plasma etching. Different etch mechanisms were responsible for lower upper part formed These angles could to some extent be controlled separately. The developed process used fabricate wideband antireflective structures with an average transmission 96.4% wavelengths between 10 50 µm. Smooth facetted edges coupling light through waveguides from above...
The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground- and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at Palomar in laboratory JPL, Hokkaido University. Manufacturing technologies devices covering wavelength ranges from optical to mid-infrared, have been maturing quickly. We will review current status technology developments supported by NASA USA (Jet Propulsion Laboratory-California Institute...
For several years, we have been developing vortex phase masks based on sub-wavelength gratings, known as Annular Groove Phase Masks. Etched onto diamond substrates, these AGPMs are currently designed to be used in the thermal infrared (ranging from 3 13 μm). Our were first installed VLT/NACO and VLT/VISIR 2012, followed by LBT/LMIRCam 2013 Keck/NIRC2 2015. In this paper, review development, commissioning, on-sky performance, early scientific results of new coronagraphic modes report lessons...