Abstract
Grating Coupled Interferometry (GCI) using high quality waveguides with two incoupling and one outcoupling grating areas is introduced to increase and precisely control the sensing length of the device; and to make the sensor design suitable for plate-based multiplexing. In contrast to other interferometric arrangements, the sensor chips are interrogated with a single expanded laser beam illuminating both incoupling gratings simultaneously. In order to obtain the interference signal, only half of the beam is phase modulated using a laterally divided two-cell liquid crystal modulator. The developed highly symmetrical arrangement of the interferometric arms increases the stability and at the same time offers straightforward integration of parallel sensing channels. The device characteristics are demonstrated for both TE and TM polarized modes.
Highlights
There is an increasing need for cost-effective, reliable and high resolution measurements of biological and chemical processes in the health, biotechnology and military areas
It is especially useful when the processes and interactions are monitored without the need of any fluorescent or radioactive labelling; by following, for example, refractive index variations caused by the inherent polarizability of biomolecules [6,7,8,9,10] or living cells [11,12,13]
In order to obtain the Grating Coupled Interferometry (GCI) interference signals, the measuring beam was phase modulated by driving the lower cell of the liquid crystal modulator (LCM) with a periodical square wave voltage shown in Fig. 3(a) The recorded interference signal during one relaxation period could be well fitted with the following analytical formula for trel
Summary
There is an increasing need for cost-effective, reliable and high resolution measurements of biological and chemical processes in the health, biotechnology and military areas. Measuring biomolecular or cellular interactions at the nanometer length scale opens up several challenging applications in basic biological, chemical and biophysical research with significant industrial relevance [1,2,3,4,5,6] It is especially useful when the processes and interactions are monitored without the need of any fluorescent or radioactive labelling; by following, for example, refractive index variations caused by the inherent polarizability of biomolecules [6,7,8,9,10] or living cells [11,12,13]. Except the relatively well-known Surface Plasmon Resonance (SPR) sensors [14], the most sensitive and promising label-free optical configurations are still in their infancy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
