Anneline Carlsen

Bio: Anneline Carlsen is an academic researcher from Technical University of Denmark. The author has contributed to research in topics: Photonic-crystal fiber & Optical field. The author has an hindex of 4, co-authored 4 publications receiving 681 citations.

Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions

Abstract: We demonstrate evanescent-wave sensing of Cy5-DNA-molecules in an aqueous solution using a photonic crystal fiber. Less than 0.8µL sample volume placed in the holes of the fiber is sufficient for reliable detection.

Photonic crystal fiber based evanescent-wave sensor for detection of biomolecules in aqueous solutions

Abstract: We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 µL is used.

Photonic crystal fiber-based evanescent-wave sensor for detection of biomolecules in aqueous solutions

Abstract: We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 µL is used.

Evanescent wave sensing using a hollow-core photonic crystal fiber

Abstract: In order to realize an efficient absorption measurement based evanescent-wave sensor, a long interaction length and a strong penetration of the optical field into the sample space is required. For an optical fiber based device, with a solid silica core immersed into a liquid sample, the strength of the evanescent field increases with decreasing core radius. When the core diameter is comparable to the wavelength of the light, a large fraction of the light propagates in the evanescent field. We demonstrate evanescent-wave sensing on aqueous solutions of fluorophore labeled biomolecules positioned in the air holes of a hollow-core photonic crystal fiber (PCF). The aqueous solutions can be positioned in close proximity to light guided in small cores without removing the coating and cladding, thus ensuring a very robust device. In order to make selective DNA detection, we coated the inside of the hollow-core PCF with a sensing layer, which by hybridization selectively immobilize specific molecules. A fluorescence measurement method, where a line-shaped laser beam expose the fiber from the side and excites the fluorophore molecules, was realized. The emitted fluorescence tunnels via the evanescent field into the fiber core(s) and is analyzed by a spectrometer at the fiber end.

Photonic Crystals for Chemical Sensing and Biosensing

Abstract: This Review covers photonic crystals (PhCs) and their use for sensing mainly chemical and biochemical parameters, with a particular focus on the materials applied. Specific sections are devoted to a) a lead-in into natural and synthetic photonic nanoarchitectures, b) the various kinds of structures of PhCs, c) reflection and diffraction in PhCs, d) aspects of sensing based on mechanical, thermal, optical, electrical, magnetic, and purely chemical stimuli, e) aspects of biosensing based on biomolecules incorporated into PhCs, and f) current trends and limitations of such sensors.

Photonic crystal fiber long-period gratings for biochemical sensing.

Abstract: We present experimental results showing that long-period gratings in photonic crystal fibers can be used as sensitive biochemical sensors. A layer of biomolecules was immobilized on the sides of the holes of the photonic crystal fiber and by observing the shift in the resonant wavelength of a long-period grating it was possible to measure the thickness of the layer. The long-period gratings were inscribed in a large-mode area silica photonic crystal fiber with a CO2 laser. The thicknesses of a monolayer of poly-L-lysine and double-stranded DNA was measured using the device. We find that the grating has a sensitivity of approximately 1.4nm/1nm in terms of the shift in resonance wavelength in nm per nm thickness of biomolecule layer.

Microstructure fibres for optical sensing in gases and liquids

Abstract: A novel water-core microstructure fibre design allows nearly ideal guidance for aqueous sensing applications. The total internal reflection by a microstructured silica–air cladding provides robust confinement of light in a fluid-filled core, if the average cladding index is sufficiently below the index of water. Numerical results show dramatically improved loss and overlap of light with the sample, compared to evanescent-field fibres, indicating a direct improvement of sensor performance. A strategy for the improvement of evanescent-wave gas sensors is also discussed.

Review of long period fiber gratings written by CO2 laser

Abstract: This paper presents a systematic review of long period fiber gratings (LPFGs) written by the CO2 laser irradiation technique. First, various fabrication techniques based on CO2 laser irradiations are demonstrated to write LPFGs in different types of optical fibers such as conventional glass fibers, solid-core photonic crystal fibers, and air-core photonic bandgap fibers. Second, possible mechanisms, e.g., residual stress relaxation, glass structure changes, and physical deformation, of refractive index modulations in the CO2-laser-induced LPFGs are analyzed. Third, asymmetrical mode coupling, resulting from single-side laser irradiation, is discussed to understand unique optical properties of the CO2-laser-induced LPFGs. Fourthly, several pretreament and post-treatment techniques are proposed to enhance the efficiency of grating fabrications. Fifthly, sensing applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based temperature, strain, bend, torsion, pressure, and biochemical sensors. Finally, communication applications of the CO2-laser-induced LPFGs are investigated to develop various LPFG-based band-rejection filters, gain equalizers, polarizers, and couplers.

Photonic crystal fibers for sensing applications

Abstract: Photonic crystal fibers are a kind of fiber optics that present a diversity of new and improved features beyond what conventional optical fibers can offer. Due to their unique geometric structure, photonic crystal fibers present special properties and capabilities that lead to an outstanding potential for sensing applications. A review of photonic crystal fiber sensors is presented. Two different groups of sensors are detailed separately: physical and biochemical sensors, based on the sensor measured parameter. Several sensors have been reported until the date, and more are expected to be developed due to the remarkable characteristics such fibers can offer.