Dr. Lhoucine Ben Mohammadi Profile

Dr. Lhoucine Ben Mohammadi

at Fraunhofer ICT-IMM

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Publications (7)

Proceedings Article | 8 May 2014 Paper

In vivo continuous glucose monitoring using a chip based near infrared sensor

L. Ben Mohammadi, S. Sigloch, I. Frese, K. Welzel, M. Göddel, T. Klotzbücher

Proceedings Volume 9129, 912929 (2014) https://doi.org/10.1117/12.2052216

KEYWORDS: Sensors, Glucose, Blood, Infrared sensors, Near infrared, Polymers, Light emitting diodes, Microfluidics, In vivo imaging, Calibration

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Proceedings Article | 8 May 2012 Paper

A minimally invasive chip based near infrared sensor for continuous glucose monitoring

L. Ben Mohammadi, S. Sigloch, I. Frese, V. Stein, K. Welzel, F. Schmitz, T. Klotzbücher

Proceedings Volume 8427, 84270K (2012) https://doi.org/10.1117/12.922381

KEYWORDS: Glucose, Sensors, Light sources, Light emitting diodes, Spectroscopy, Absorbance, Near infrared, Microfluidics, Absorption, Signal to noise ratio

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Assessment of glycaemia in diabetes is crucially important for prevention of both, acute and long term complications. Continuous glucose monitoring (CGM) is certainly the most appropriate way for optimizing the glycaemic control, since it prevents or delays the progression of complications associated with hypo- or hyperglycaemic events, reducing morbidity, mortality, and overall costs in health care systems. In this paper we describe the concept and first in vitro results of a minimally invasive, chip-based NIR-Sensor for continuous glucose monitoring. The sensor concept is based on difference infrared absorption spectroscopy, which was evaluated within laboratory measurements of D+-Glucose dissolved in water. The laboratory measurements revealed a linear relationship between glucose concentration and the integrated difference spectroscopy signal with a coefficient of determination of 99.6% in the concentration range of 0- 500 mg/dL. Suitable wavelength bands were identified in which the correlation is preserved and commercial light sources are available for realisation of a spectrometer-less, integrated NIR-sensor. In the designed sensor the component area (non-disposable) is separated from the detection area (disposable, low-cost). The disposable part of the sensor is fluidically connected to a micro-dialyses needle, accessing glucose subcutaneously via the ISF (interstitial fluid) or intravascularly. The non-disposable part contains all the optical elements, like LED´s and photo-detectors. The in- and out-coupling of the optical signal is achieved across the plane of the chip by using total internal reflection on mirrors integrated into the fluidic chip. The glucose is continuously measured by considering the difference signals of light at the corresponding wavelengths, as a function of time or in defined intervals if the light sources are modulated. The in-vitro measurements show an absolute error of about 5 mg/dL with a relative error of 5% for glucose concentrations larger than 50 mg/dL and about 12 % in the hypoglycemic range (<50 mg /dL).

Proceedings Article | 22 February 2012 Paper

Nano-structured surfaces by laser interference lithography and fs-laser direct writing as substrates for surface-enhanced Raman spectroscopy

L. Ben Mohammadi, N. Hundertmark, F. Kullmann, F. Fleissner, T. Klotzbücher

Proceedings Volume 8244, 82440D (2012) https://doi.org/10.1117/12.906323

KEYWORDS: Raman spectroscopy, Surface enhanced Raman spectroscopy, Silver, Lithography, Metals, Spectroscopy, Molecules, Semiconductor lasers, Nanostructuring, Surface plasmons

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Proceedings Article | 14 May 2010 Paper

A low cost mid-infrared sensor for on line contamination monitoring of lubricating oils in marine engines

L. Ben Mohammadi, F. Kullmann, M. Holzki, S. Sigloch, T. Klotzbuecher, J. Spiesen, T. Tommingas, P. Weismann, G. Kimber

Proceedings Volume 7726, 77260M (2010) https://doi.org/10.1117/12.854476

KEYWORDS: Sensors, Absorbance, Calibration, Contamination, Water, Ocean optics, Signal detection, Absorption, Mid-IR, Infrared sensors

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The chemical and physical condition of oils in marine engines must be monitored to ensure optimum performance of the engine and to avoid damage by degraded oil not adequately lubricating the engine. Routine monitoring requires expensive laboratory testing and highly skilled analysts. This work describes the adaptation and implementation of a mid infrared (MIR) sensor module for continued oil condition monitoring in two-stroke and four-stroke diesel engines. The developed sensor module will help to reduce costs in oil analysis by eliminating the need to collect and send samples to a laboratory for analysis. The online MIR-Sensor module measures the contamination of oil with water, soot, as well as the degradation indicated by the TBN (Total Base Number) value. For the analysis of water, TBN, and soot in marine engine oils, four spectral regions of interest have been identified. The optical absorption in these bands correlating with the contaminations is measured simultaneously by using a four-field thermopile detector, combined with appropriate bandpass filters. Recording of the MIR-absorption was performed in a transmission mode using a flow-through cell with appropriate path length. Since in this case no spectrometer is required, the sensor including the light source, the flowthrough- cell, and the detector can be realised at low cost and in a very compact manner. The optical configuration of the sensor with minimal component number and signal intensity optimisation at the four-field detector was implemented by using non-sequential ray tracing simulation. The used calibration model was robust enough to predict accurately the value for soot, water, and TBN concentration for two-stroke and four-stroke engine oils. The sensor device is designed for direct installation on the host engine or machine and, therefore, becoming an integral part of the lubrication system. It can also be used as a portable stand-alone system for machine fluid analysis in the field.

Proceedings Article | 24 February 2009 Paper

Active integrated components for fluid control in automatic analytical chip-based systems

F. von Germar, J. Claußen, R. Gransee, E. Schaeffer, L. Mohammadi, T. Klotzbücher

Proceedings Volume 7207, 720709 (2009) https://doi.org/10.1117/12.812012

KEYWORDS: Sensors, Prisms, Light emitting diodes, Microfluidics, Liquids, Light sources, Fiber couplers, Control systems, Modulation, Photodiodes

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Proceedings Article | 14 May 2008 Paper

Integrated optical sensor for liquid control in micro-fluidic channel systems

Frithjof v. Germar, Thomas Klotzbücher, Lhoucine Ben Mohammadi, Jan Claussen

Proceedings Volume 6992, 69920K (2008) https://doi.org/10.1117/12.784138

KEYWORDS: Sensors, Prisms, Liquids, Light emitting diodes, Microfluidics, Polymers, Water, Reflection, Control systems, Light sources

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Proceedings Article | 19 July 1999 Paper

Integrated optical pickup for optical disks

Theo Tschudi, Lingli Wang, Svetomir Stankovic, Mathias Hain, Shanti Bhattacharia, Daniel Diaz, Lhoucine Benmohammadi, Chialou Karaboue, Edgar Pawlowski, Margit Ferstl

Proceedings Volume 3749, (1999) https://doi.org/10.1117/12.354811

KEYWORDS: Integrated optics, Optical discs, Liquid crystals, Digital video discs, Diffractive optical elements, Packaging, Lenses, Applied physics, Compact discs, Optical storage

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Showing 5 of 7 publications

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