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Effect of surface structuring onto the efficiency of the in- and out-coupling of light from a chip in Lab-on-a-chip approaches with optical detection

 
: Frese, Ines; Gransee, Rainer

:

Cullum, B.M. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Smart biomedical and physiological sensor technology X : 1 - 2 May 2013, Baltimore, Maryland, United States
Bellingham, WA: SPIE, 2013 (Proceedings of SPIE 8719)
ISBN: 978-0-8194-9510-5
Paper 87190D, 11 S.
Conference "Smart Biomedical and Physiological Sensor Technology" <10, 2013, Baltimore/Md.>
European Commission EC
FP7; 261810; MULTISENSE CHIP
Englisch
Konferenzbeitrag
Fraunhofer ICT-IMM ()
colorimetry; cylindrical lenses; fluorescence; spectroscopy; Lab-on-a-Chip; lenses; luminescence; mirrors; optical sensing; polymer

Abstract
Optical detection methods have been implemented on micro-fluidic chips containing channels or cavities of different geometries e.g. for colorimetry or fluorescence measurements with excitation within the chip plane [1-2]. The most prominent problem of the read-out from a micro-fluidic chip is the limitation of the optical yield. Without e.g. an immersion liquid for compensation of the total reflection on the boundary, only about 11-13% of rays cross over the boundary from a polymer chip to air. One efficient method to increase the optical yield from a chip is a ray reorientation inside of the chip using an additional surface structure creating new incident refraction conditions on the boundary before rays are leaving the chip. The use of 45°-tilted mirror arrangements for in- and out-coupling of the fluorescence signal from a micro-fluidic chip and the realization of this principle for low-cost fluorescence detection systems have been published [3].
This paper includes the investigation of the effect of different tilt angles of total reflection and metallized-surface mirrors for an analyte volume emitter, using the ray-tracing simulation tool OptiCAD10. Furthermore, an estimation of the influence of a surface-emitted signal for different geometries of metallized detection cells with or without a combination with external lenses on the out-coupling efficiency will be presented. The best result of an out-coupling efficiency increase of 10 times was achieved for a combination of a structured and metallized detection cell with an external cylindrical lens.

: http://publica.fraunhofer.de/dokumente/N-401933.html