We report an innovative label-free biosensor based on statistical analysis of several whispering gallery modes spectral shifts in polystyrene fluorescent microspheres using a custom microflow cytometer. Whispering gallery modes analysis enables detection of nanometer-sized analytes showing promising possibilities for virus, bacteria and molecular detection. To demonstrate this, fluorophore-doped microspheres of the appropriate size parameter are mixed in an aqueous solution. Then, a syringe pump pushes the solution through a fiber optic flow cell where a laser beam illuminates the analysis area to excite the microspheres and their fluorescence is collected. This device provides a low-cost and user friendly solution that could enhance spectrum acquisition rates up to 5 spectra per second thanks to the considerable amount of microspheres flowing through the excitation area per unit time. Finally, the fluorescence spectra are statistically investigated using an instantaneous measurement of apparent refractive index algorithm to determine a reliable value for the refractive index of the environment since the exact radius of the microsphere scanned is unknown. This refractive index becomes an effective value for the local perturbation caused by inhomogeneities on the microsphere surface and hence, determines whether or not inhomogeneities, such as bacteria, are adsorbed by comparing to a control sample. Combining a flow cell with our detection algorithm, we reduce the period of a 50 microspheres experiment from 161 minutes to 14 minutes when the flow rate is 2000 µl/h and the microsphere concentration is 5 µsphere/µl.
SpIOMM is an imaging Fourier transform spectrometer designed to obtain the visible range (350 - 850 nm) spectrum of
every light source in a circular field of view of 12 arcminutes in diameter. Attached to the 1.6-m telescope of the
Observatoire du Mont Megantic in southern Quebec. We present here some results of three successful observing runs in
2007, which highlight SpIOMM's capabilities to map emission line objects over a very wide field of view and a broad
spectral range. In particular, we discuss data cubes from the planetary nebula M27, the supernova remnants NGC 6992
and M1, the barred spiral galaxy NGC7479, as well as Stephan's quintet, and interacting group of galaxies.
We present the most recent technical improvements on SpIOMM, an Imaging Fourier Transform Spectrometer (IFTS)
attached to the 1.6 telescope of the Mont Megantic Observatory. The recent development of SpIOMM demonstrates that
the concept of IFTS for ground telescopes is a promising astronomical 3D spectroscopy technique for multi-object
spectroscopy and multi-band imaging. SpIOMM has been developed through a collaboration between Universite Laval
and the industry (ABB Bomem). It is designed for optical observations from the near UV (350 nm) to the near IR (850
nm) with variable spectral resolution. The circular FOV of the instrument covers 12' in diameter. We have recently
improved the servo system algorithm which now controls the mirror displacement and alignment at a rate of ~7kHz.
Hardware improvements to the servo and the metrology system will be described along with their impacts on
performance in the laboratory and in observing conditions. The instrument has successfully been operated at the 1.6
meter telescope this year using the revised control systems and acquired several datacubes. We will discuss some issues
regarding the sensitivity to environmental conditions implied by the use of such an instrument. An overview of the
datacube reduction procedure will show some solutions proposed for observational problems encountered that affect the
quality of the data such as sky transmission variations, wind, changing gravity vector and temperature.
We present an overview of SpIOMM, an Imaging Fourier Transform Spectrometer (IFTS) for astronomy developed at University Laval in collaboration with ABB, INO and the Canadian Space Agency. SpIOMM, attached to the 1.6 meter (f/8) telescope at the Observatoire du mont Megantic in Quebec. It is a Michelson-type interferometer capable of
obtaining the visible spectrum (from 350 nm to 900 nm) of every light source within its 12 arcminute circular field of view. This design will allow the correction of variable sky transmission. It consists of a dual output port and the total throughput is exploited by two CCDs used as detectors. We present the concept and design of this unique instrument. A metrology system combined with a dynamic alignment assures a good sampling and mirror alignment during the entire acquisition sequence. This particular servo control is explained and demonstrated and its capabilities and performance
are discussed. We introduce the use of specific bandpass filters centered on the most important groups of emission lines which, when combined with spectral folding algorithms, allows us to reach high spectral resolution (R = 25 000, or 1 cm-1). Astronomical data collected by SpIOMM in 2004-2005 are also presented.
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