G. Roger

Surface plasmon resonance spectro-imaging sensor for biomolecular surface interaction characterization

Surface plasmon resonance (SPR) techniques have become, over the last ten years, powerful tools to study biomolecular surface interaction kinetics in real-time without any use of labels. The highest resolution is currently obtained using spectroscopic SPR systems through the measurement of the complete surface plasmon resonance curve in angular or spectral configuration. But, these systems are limited to a few independent channels (<10). In order to expand their capability to an array format, SPR sensors have also been developed in an imaging mode, allowing parallel monitoring of hundreds of sensing spots onto a camera. However, such sensors rely on the intensity variation measurement at a single position of the resonance spectrum, hence resulting in smaller resolution. We present in this work a SPR spectro-imaging system which aims at keeping the advantage of a mono-channel SPR sensor based on the full resonance curve measurement while introducing an additional spatial dimension (linear multi-spot array). The system is based on the illumination of a biochip through a vertical slit (y-dimension) by a white light source. The reflected light spectrum obtained through a diffracting grating is then imaged on the x-dimension of the camera. The complete spectral resonance curve of a full column of sensing spots can be monitored in parallel and in real-time. We demonstrate that data processing is key to reduce the noise and to improve the resolution. We report on the detection of signals with resolution comparable to the one obtained with a classical SPR mono-channel spectroscopic sensor (3.5 x 10(-7) Refractive Index Unit), gaining an order of magnitude compared to SPR imaging sensors. Eventually, we show that short base DNA-DNA hybridizations with concentrations as low as 100 pM can be detected and discriminated in a few tens of minutes following injection by the SPR spectro-imaging system.

Importance of dye host on absorption, propagation losses, and amplified spontaneous emission for dye-doped polymer thin films

The absorption spectra of dye-doped polymer thin films made from a variety of five dyes and six matrices, either organic or organomineral, are analyzed to evaluate the residual absorption in the red wavelength tail and in particular at amplified spontaneous emission (ASE) wavelengths. An absorption cutoff wavelength is defined as the extrapolated wavelength at which the absorption losses are expected to become negligible compared to the structure losses. Such absorption-spectrum-extrapolated wavelengths are compared to the ASE wavelengths and found to correlate for most of the dye-matrix couples. The propagation losses of PM597-doped organic polymers are also measured and accordingly found to increase with the glass transition temperature of the host matrix.

Dye-doped sol–gel materials for two-photon absorption induced fluorescence

Abstract Two-photon absorption (TPA) and subsequent fluorescence properties of laser dyes are retained when doped into solid state sol–gel materials. These properties were demonstrated to be applicable in true 3D displays.

Femtosecond pulses at 800 nm by passive mode locking of Rhodamine 700

We report the passive mode locking of a Rhodamine 700 dye laser in the near infrared. Using a short cavity in order to avoid multiple pulses and by adjusting the intracavity dispersion, we have produced 50-fsec pulses at 800 nm with HITCI as the saturable absorber.

58 fs pulse generation near 685 nm from a passively mode locked dye laser

Abstract We report here the passive mode locking of an energy transfer continuous wave dye laser operating in the red spectral region. Using the dye DQTCI as saturable absorber and a mixture of R6G and SR 101 as gain medium, pulses as short as 58 fs around 685 nm have been generated in a colliding pulse mode locked dye laser with an adjustable intracavity group velocity dispersion. Furthermore, experimental observation of high order nonsymmetrical soliton-like pulses in this laser is also reported.

Surface plasmon resonance spectro-imaging sensor and associated data processing for biomolecular surface interaction characterization

Surface plasmon resonance (SPR) technique has become over the last ten years a powerful tool allowing the analysis and the detection of biomolecular surface interactions in real time without any use of labels. The highest sensitivity is currently obtained using a mono-spot sensor through the measurement of the complete surface plasmon resonance curve (in angular or spectral configuration), since it is inherently more robust than a single intensity variation measurement. However, this last approach is used to perform SPR imaging, allowing parallel monitoring of hundreds of sensing spots onto a camera. We present in this work a SPR spectro-imaging system including dynamical multi-spectral capabilities. The system is based on the illumination over a vertical slit of the biochip (y-dimension) by a white light source. The spectrum of the reflected light obtained through a grating is then imaged on the x dimension of the camera. The complete spectral resonance curve of a full column of sensing spots can be monitored in parallel and in real-time by this simple apparatus. The influence of the main instrumental parameters and of different data processing are investigated. Clear improvements of the sensitivity have been obtained on refractometric tests and preliminary results on DNA:DNA interactions are finally presented.

Spatio-temporal self-calibration of optical dynamical biochip

The authors propose a self-calibration approach to compensate the response dispersion on biochips due to the non homogeneous surface layers. Such effect of probe concentration has been quantified in the case of a DNA biochip.

High Power CW Diode-Pumped LiSaF Laser

This paper is devoted on Cr:LiSAF laser pumped by cw visible GaAlInP diode at 670nm. Ouput power of more than 60 mW at 850 nm has been obtained with a 500 mW pump laserdiode and the laser is tunable from 810 to 900 nm.