We present three optical multi-channels spectrometers for the interrogation of label-free biosensors based on different kinds of transducers : resonant nanopillars (RNP), microring resonators (MRR), localized and propagative surface plasmon resonance (LSPR and SPR). Light is collected from the multi-channel biosensors (up to 12-channels) with optical fibers and is remapped to a packed straight line forming the input slit of the spectrometers. The combination of high resolution CMOS sensors and embedded signal processing makes it possible to extract the resonant wavelengths of the transducers with a precision in the range of 1-20 pm depending on the type of transducer. The performance of the three transducer / spectrometer systems has been evaluated in the framework of EU and regional projects for the monitoring of chemical pollutants found in oceanic waters (FP7 - EnviGuard), crop health monitoring (Interreg France-Wallonie-Vlaanderen - SmartBioControl/BioSens) and bioreactor monitoring (EutoTransBio - APTACHIP).
In this paper, we present an original concept of plasmonic-related instrumentation platform dedicated to diagnostic biosensing tests out of the laboratory. The developed instrumental platform includes both disposable one-use microfluidic affinity biochip and compact optical readout device for biochip monitoring involving mobile Internet devices for data processing and communication. The biochip includes both microfluidic and optical coupling structures formed into a single plastic slab. The microfluidic path of the biochip operates in passive capillary pumping mode. In the proof-of-concept prototype, we address specifically the sensing format involving Surface Plasmon Resonance phenomenon. The biochip is plugged in the readout device without the use of an index matching fluid. An essential advantage of the developed biochip is that its implementation involves conventional hot embossing and thin film deposition process, perfectly suited for mass production of low-cost microfluidic biochip for biochemical applications.
KEYWORDS: Light sources and illumination, LED lighting, Monte Carlo methods, Light emitting diodes, Scattering, Energy conversion efficiency, Light scattering, Geometrical optics, Printing, Optimization (mathematics)
In this paper, we present an original method of dot pattern generation dedicated to large-size format light guide plate (LGP) design optimization, such as photo-bioreactors, the number of dots greatly exceeds the maximum allowable number of optical objects supported by most common ray-tracing software. In the proposed method, in order to simplify the computational problem, the original optical system is replaced by an equivalent one. Accordingly, an original dot pattern is splitted into multiple small sections, inside which the dot size variation is less than the ink dots printing typical resolution. Then, these sections are replaced by equivalent cells with continuous diffusing film. After that, we adjust the TIS (Total Integrated Scatter) two-dimensional distribution over the grid of equivalent cells, using an iterative optimization procedure. Finally, the obtained optimal TIS distribution is converted into the dot size distribution by applying an appropriate conversion rule. An original semi-empirical equation dedicated to rectangular large-size LGPs is proposed for the initial guess of TIS distribution. It allows significantly reduce the total time needed to dot pattern optimization.
We present a thermoreflectance-based metrology concept applied to compound semiconductor thin films off-line
characterization in the solar cells scribing process. The presented thermoreflectance setup has been used to evaluate the
thermal diffusivity of thin CdTe films and to measure eventual changes in the thermal properties of 5 μm CdTe films
ablated by nano and picosecond laser pulses. The temperature response of the CdTe thin film to the nanosecond heating
pulse has been numerically investigated using the finite-difference time-domain (FDTD) method. The computational and
experimental results have been compared.
We present the design, implementation and characterization of an integrated surface plasmon resonance
biosensor chip involving diffractive optical coupling elements avoiding the need of prism coupling. The
integrated sensor chip uses the angular interrogation principle and includes two diffraction gratings and the SPR
sensing zone. The theoretical design is presented as well as the fabrication procedure. Experimental results,
using reference index fluids, are compared to theoretical predictions and prism coupling experimental results.
We believe that this architecture is perfectly suitable for low cost and reproducible SPR biochemical sensor
chips since the sensing zone can be functionalized as any other one.
Surface Plasmons Resonance (SPR) architectures involving multi-wavelength interrogation is an attractive alternative
for droplet biosensing. In this work, we address two detection formats experimentally investigated by our research
group. The first one involves an angular scanning combining one near-IR and one visible light probes. It enables to
increase the number of parameters for numerical fitting, which improves the precision of measurement. The second
concept involves the SPR Coupler and Disperser sensor principle, where the spectrum analysis is performed on each
detector pixel using the same diffraction grating that is employed for the optical coupling of the incident light with the
Surface Plasmons Resonance (SPR) architectures based on grating coupler/disperser combination is an attractive
alternative for spectral-based sensing. We present a new concept where the plasmon coupling occurs through thin film
grating and sensing occurs via the first diffraction order in reflective or transmitive mode. The developed geometry is
dedicated to droplet sensing. The extension of the architecture to bi-dimensional array of sensors is also facilitated. This
paper describes several designs of sensors. The analysis of their theoretical performances is demonstrated and compared,
including a sensitivity evaluation.
This paper describes a new concept related to the bolometric micromechanical sensors for detecting far IR and THz radiation. We believe that this concept permits a low cost and ease of fabrication of large bi-dimensional array of sensors with an enhanced signal-to-noise ratio. The micromechanical sensor comprises a thermo-sensitive bi-material (multi-material) micro-cantilever beam with a selective absorber dedicated to far IR and THz radiation energy, and optical readout system based on surface plasmon resonance for detecting the bending of the micro-cantilever element. To increase the radiation detector sensitivity, the SPR phenomenon is used for cantilever deflection monitoring.
This paper describes a new concept related to the micromechanical sensors for detecting the presence and concentration of chemical substances and/or biological organisms. We believe that this concept allow for a low cost and ease of fabrication of a large bi-dimensional array of sensors with an enhanced signal-to-noise ratio. A bi-dimensional array of micro-cantilever coated with different types of sensing layer enables to identify a characteristic chemical composition of the gas in real-time mode. The selective molecular absorption by cantilever sensing layer will produce cantilever bending proportional to the concentration of molecules. To increase the gas sensor sensitivity, the SPR phenomenon is used for cantilever deflection monitoring.