Spectroscopy ultra-sensitive

Warken, F. Vetsch, E. Meschede, D. Sokolowski, M. Rauschenbeutel, A., Ultra sensitive surface absorption spectroscopy using sub wavelength diameter optical fibers, Opt. Express... 

In contrast to SPFS, SPR, and SPDS are tools that can study biomolecular interactions without external labels. They share the same category of label-free biosensors with the reflectometry interference spectroscopy (RIfS) [46], waveguide spectroscopy [47], quartz crystal microbalance (QCM) [48], micro-cantilever sensors [49], etc. Although the label-free sensors cannot compete with SPFS in terms of sensitivity [11], they are however advantageous in avoiding any additional cost/time in labeling the molecules. In particular, the label-free detection concept eliminates undue detrimental effects originating from the labels that may interfere with the fundamental interaction. In this sense, it is worthwhile to develop and improve such sensors as instruments complementary to those ultra-sensitive sensors that require labels. 

Gryczynski, Z., Malicka, J., Gryczynski, I., Matveeva, E., Geddes, C. D., Aslan, K., and Lakowicz, J. R. (2004). Metal-enhanced fluorescence a novel approach to ultra-sensitive fluorescence sensing assay platforms. Biomedical Vibrational Spectroscopy and Biohazard Detection Technologies 5321 275-282. 

Ruan C, Wang W, Gu B (2006) Rapid and ultra-sensitive detection of alkaline phosphatase using surface enhanced Raman spectroscopy. Anal Chem 78 3379-3384... 

The ultra-sensitive technique of LEAFS was developed and exploited for the analysis of snow and ice to be carried out at the Institute of Spectroscopy of the Russian Academy of Science (ISAN) (46). This technique allows the direct determination of toxic metals in polar snow and ice to be carried out at and below the pg/g level in sample volumes of less than 100 pi. This is an important issue considering that very often the volume of sample obtained after the decontamination procedures amounts to just a few tens of milliliters in the best case and that this must be subdivided into different aliquots for a complete chemical characterisation. 

SLS = synchronous luminescence spectroscopy SPE = solid phase extraction USERIA = ultra-sensitive enzyme radioimmunoassay... 

Wen-Bin, Y., Ultra Sensitive Trace Gas Detection using Cavity Ringdown Spectroscopy, IFPAC January 21—24, 2001, Amelia Island, FL, USA www.Meeco.-com www.tigeroptics.com ... 

Kinetic Inductance Detectors (KIDs) are the most promising candidate for future space and ground based spectroscopy at sub-millimetre wavelengths (Mazin 2009 Zmuidzinas 2012 Baselmans 2012). They provide a promising solution to the problem of producing large format arrays of ultra sensitive detectors for astronomy. Traditionally KIDs have been constructed from superconducting quarter-wave resonant elements capacitively coupled to a co-planar feed line. 

Yea GH, Lee S, Kyong JB, Choo J, Lee EK, Joo SW, Lee S (2005) Ultra-Sensitive Trace Analysis of Cyanide Water Pollutant in a PDMS Microfluidic Channel Using Surface-Enhanced Raman Spectroscopy. Analyst 130 1009-1011... 

Hu J., Ultra-sensitive chemical vapor detection using micro-cavity photothermal spectroscopy. Opt Express, 18, 22174-22186 (2010). Lin H., Zou Y, and Hu J., Double resonance 1-D photonic crystal cavities for single-molecule mid-infrared photothermal spectroscopy Theory and design. Opt Lett, 37,1304-1206 (2012). 

Ultra-sensitive detection of individual gold nanoparticles spectroscopy and applications to biology, L. Cognet and B. Lounis, Gold Bull., 2008, 41, 139. 

As discussed above, it is desirable to use large, almost grazing angles of incidence in RAIR spectroscopy in order to maximize the sensitivity of the technique to ultra-thin films. Using such large angles of incidence usually requires the substrates to be at least a few centimeters in length. This severely limits the spatial... 

While electron or ion beam techniques can only be applied under ultra-high vacuum, optical techniques have no specific requirements concerning sample environment and are generally easier to use. The surface information which can be obtained is, however, quite different and mostly does not contain direct chemical information. While with infra-red attenuated total reflection spectroscopy (IR-ATR) a deep surface area with a typical depth of some micrometers is investigated, other techniques like phase-measurement interference microscopy (PMIM) have, due to interference effects, a much better surface sensitivity. PMIM is a very quick technique for surface roughness and homogeneity inspection with subnanometer resolution. 

The SEXAFS teehnique is a partieular surface sensitive detection mode applied to an EXAFS measurement, performed in a particular environment, the Ultra High Vacuum, which is needed in order to prepare and protect the atomic-scale eleanliness of surface and interface systems for the whole time length of the experiment. As such the technique borrows equipment and procedures from the surface science spectroscopies, and exploitation procedures of the synchrotron radiation source from the conventional, non vacuum, EXAFS method. The studies described below have been performed at the Laboratoire pour T Utilisation du Rayonnement Electro-magnetique (LURE) exploiting synehrotron radiation from the storage ring DCI... 

Techniques of electron spectroscopies have emerged to become the principal means for investigating electronic structures of solids and surfaces (Rao, 1985 Mason et al, 1986). Most of these techniques involve the analysis of the kinetic energy of the ejected or scattered electrons. Some of the important techniques of electron spectroscopy used to study solids are photoelectron spectroscopy using X-rays (XPS) or UV radiation (UVPS), Auger electron spectroscopy (AES) and electron energy loss spectroscopy, (EELS). All these techniques are surface-sensitive and probe 25 A or less of solids. Cleanliness of the surfaces and ultra-high vacuum ( 10 — 10 " torr) are there-... 

The use of ultra-violet (UV) spectroscopy for on-line analysis is a relatively recent development. Previously, on-line analysis in the UV-visible (UV-vis) region of the electromagnetic spectrum was limited to visible light applications such as color measurement, or chemical concentration measurements made with filter photometers. Three advances of the past two decades have propelled UV spectroscopy into the realm of on-line measurement and opened up a variety of new applications for both on-line UV and visible spectroscopy. These advances are high-quality UV-grade optical fiber, sensitive and affordable array detectors, and chemometrics. 

It is perhaps obvious that the nature of the interface between a molecular solid (polymer) and a (clean) metal surface is not necessarily equivalent to the interface formed when a metal is vapor-deposited (essentially atom-by-atom ) on to the (clean) surface of the polymer or molecular solid. Atoms of all metals are active in the form of individual atoms , even gold atoms. In the context of the new polymer LEDs, some of the works discussed in chapter 7 involve the study of the early stages of formation of the interface in the latter configuration (metal-on-polymer interfaces). Very little has been reported on conjugated polymer-on-metal interfaces, however, primarily because of the difficulties in preparing monolayers of polymer materials on well defined metal substrates appropriate for study (via PES or any other surface sensitive spectroscopy). The issues discussed below are based upon information accumulated over two decades of involvement with the surfaces of condensed molecular solids and conjugated polymers in ultra-thin form, represented by the examples in the previous chapter. 

The experiments were performed in two different ultra high vacuum (UHV) chambers using two different Pt(lll) single crystals. The X-ray photoelectron spectra were obtained in a chamber with a base pressure of lxlO" Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped with low energy electron diffraction (LEED), an X-ray photoelectron spectrometer (XPS), a quadrupole mass spectrometer (QMS) for temperature programmed desorption (TPD), and a Fourier transform infrared spectrometer (FTIR) for reflection absorption infrared spectroscopy (RAIRS). All RAIRS and TPD experiments were performed in a second chamber with a base pressure of 2 X 10 ° Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped for LEED, Auger electron spectroscopy (AES) and TPD experiments with a QMS. The chamber is coupled to a commercial FTIR spectrometer, a Bruker IFS 66v/S. To achieve maximum sensitivity, an... 

The emergence in the 1960s of ultra-high-vacuum techniques, structural studies through LEED and surface sensitive spectroscopies became recognised as the surface science approach to catalysis, answering many of the issues raised in Taylor s paper. It was, however, the last paragraph of his paper that made a particular impression on me ... 

---