English
norskBlar i forfatter "Hellesø, Olav Gaute"
Viser treff 1-16 av 16
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Characterization of a waveguide Mach-Zehnder interferometer using PDMS as a cover layer
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015)A Mach-Zehnder interferometer made with shallow rib waveguides is studied experimentally and using simulations. The rib-height giving single-mode guidance is found as function of core thickness and polarization. Devices have been made using shallow rib waveguides (5 nm rib height) in silicon nitride. The sensitivity and the limit of detection (LOD) is studied experimentally regarding the length of ... -
Demonstrating low Raman background in UV-written SiO2 waveguides
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-09-06)Raman spectroscopy can give a chemical ’fingerprint’ from both inorganic and organic samples, and has become a viable method of measuring the chemical composition of single biological particles. In parallel, integration of waveguides and microfluidics allows for the creation of miniaturized optical sensors in lab-on-a-chip devices. The prospect of combining integrated optics and Raman spectroscopy ... -
Dielectric microsphere manipulation and chain assembly by counter-propagating waves in a channel waveguide
(Journal article; Tidsskriftartikkel; Peer reviewed, 2007) -
Dielectric optical nanoantennas
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-22)Nanophotonics allows the manipulation of light on the subwavelength scale. Optical nanoantennas are nanoscale elements that enable increased resolution in bioimaging, novel photon sources, solar cells with higher absorption, and the detection of fluorescence from a single molecule. While plasmonic nanoantennas have been extensively explored in the literature, dielectric nanoantennas have several ... -
Evaluation of crystalline structure quality of Czochralski-silicon using near-infrared tomography
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-22)In this work, three silicon samples are subject to tomographic scans using a 1.6μm laser. The samples were prematurely terminated due to anomalies during the Czhochralski-process. They are taken as analogues of the in situ crystal, where one sample has known aberrant structure in its lowermost 45 mm. The results of the tomographic scans show a distinct difference in transmission profile between ... -
Metasurface supporting quasi-BIC for optical trapping and Raman-spectroscopy of biological nanoparticles
(Journal article; Tidsskriftartikkel, 2023-02-09)Optical trapping combined with Raman spectroscopy have opened new possibilities for analyzing biological nanoparticles. Conventional optical tweezers have proven successful for trapping of a single or a few particles. However, the method is slow and cannot be used for the smallest particles. Thus, it is not adapted to analyze a large number of nanoparticles, which is necessary to get statistically ... -
Optical transport, lifting and trapping of micro-particles by planar waveguides
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-03-03)Optical waveguides can be used to trap and transport micro-particles. The particles are held close to the waveguide surface by the evanescent field and propelled forward. We propose a new technique to lift and trap particles above the surface of the waveguides. This is made possible by a gap between two opposing, planar waveguides. The field emitted from each of the waveguide ends diverge fast, away ... -
Optical trapping and propulsion of red blood cells on waveguide surfaces
(Journal article; Tidsskriftartikkel; Peer reviewed, 2010) -
Optical trapping in air on a single interference fringe
(Journal article; Tidsskriftartikkel, 2023)Stable and reproducible trapping in air of 1 µm and 500 nm dielectric particles has been realized using a dual beam optical fiber tweezers with cleaved commercial single mode fibers. The influence of the interference fringes of the two coherent and counter-propagating trapping beam is investigated by controlling the fringe visibility. Optical trapping on a series of upto10 fringes or trapping on ... -
Rib waveguides for trapping and transport of particles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-02-23)Rib waveguides are investigated as an alternative to strip waveguides for planar trapping and transport of microparticles. Microparticles are successfully propelled along the surface of rib waveguides and trapped in the gap between opposing rib waveguides. The trapping capabilities of waveguide end facets formed by a single and opposing waveguide geometries are investigated. The slab beneath a rib ... -
Sensitive on-chip methane detection with a cryptophane-A cladded Mach-Zehnder interferometer
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-24)We report a methane sensor based on an integrated Mach-Zehnder interferometer, which is cladded by a styrene-acrylonitrile film incorporating cryptophane-A. Cryptophane-A is a supramolecular compound able to selectively trap methane, and its presence in the cladding leads to a 17-fold sensitivity enhancement. Our approach, based on 3 cm-long low-loss Si3N4 rib waveguides, results in a detection limit ... -
Serial Raman spectroscopy of particles trapped on a waveguide
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013)We demonstrate that Raman spectroscopy can be used to characterize and identify particles that are trapped and propelled along optical waveguides. To accomplish this, microscopic particles on a waveguide are moved along the waveguide and then individually addressed by a focused laser beam to obtain their characteristic Raman signature within 1 second acquisition time. The spectrum is used to distinguish ... -
Single-mode limit and bending losses for shallow Rib Si3N4 waveguides
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-07)The single-mode limit and bending losses for shallow rib waveguides are studied using the full vectorial film mode matching method. The maximum rib height for single-mode waveguides is found to be on the order of 10 nm for a rib width of 2 m and a wavelength of 785 nm, with the exact value depending on the core thickness and the polarization. Bending losses are calculated as a function of several ... -
Sorting of polystyrene microspheres using a Y-branched optical waveguide
(Journal article; Tidsskriftartikkel; Peer reviewed, 2005) -
Structured illumination microscopy using a photonic chip
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-04-11)Structured illumination microscopy (SIM) enables live-cell super-resolution imaging of subcellular structures at high speeds. At present, linear SIM uses free-space optics to illuminate the sample with the desired light patterns; however, such arrangements are prone to misalignment and add cost and complexity to the microscope. Here, we present an alternative photonic chip-based two-dimensional SIM ... -
Velocity distribution of Gold nanoparticles trapped on an optical waveguide
(Journal article; Tidsskriftartikkel; Peer reviewed, 2005)
