Cavity ring-down spectroscopy of molecularly thin iodine layers

Kleine, D.; Lauterbach, Jörg; Kleinermanns, Karl; Hering, P.

doi:10.1007/s003400000453

Cited by 37 publications

(21 citation statements)

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“…For supported clusters, cavity ringdown spectroscopy (CRDS), due to its high sensitivity and the fact that the background signal of the substrate is fully taken into account, appears to be the method of choice to study such highly diluted systems. Up to now, CRDS has mainly been applied to systems in the gas phase [16,17], but also in the liquid phases [18], as well as to thin films [19][20][21] and adsorbed molecules [22,23]. Work on supported nanosystems has been restricted to gold nanocrystals with a broad size distributions [24] or to infrared studies of fullerene films [25].…”

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confidence: 98%

Optical Absorption Spectrum of Gold Atoms Deposited onSiO2from Cavity Ringdown Spectroscopy

et al. 2005

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The optical properties of gold atoms supported on amorphous silica (alpha-SiO2) were studied experimentally and theoretically in the visible range. Samples were prepared in situ by depositing Au atoms at low coverages (5 x 10(12) cm(-2)) in UHV, and the optical absorption spectra were recorded by cavity ringdown spectroscopy. The atomic absorption bands can be attributed to gold atoms trapped at [triple bond] Si-O(.-) and [triple bond]Si-O(-) defect sites. The absence of optical transitions typical for Au(2) shows that the atoms are efficiently anchored at these defect sites, preventing diffusion and aggregation. Furthermore, these experimental results reveal that it is now possible to study optical properties of well-defined nanostructures at surface coverages as low as 5 x 10(11) cm(-2).

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confidence: 98%

Optical Absorption Spectrum of Gold Atoms Deposited onSiO2from Cavity Ringdown Spectroscopy

et al. 2005

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“…In order to detect both isotopomers without cross sensitivity, we had to use a tunable laser system. The light of a CO overtone laser was mixed with an electrooptical modulator which produces tunable microwave side bands (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). In this way, we reach a spectral covering of about 14% in the wavelength range between 2.6 and 4 µm.…”

Section: Results With Calos In the Mirmentioning

confidence: 99%

Atmospheric trace gas analysis with cavity ring‐down spectroscopy

Kleine

Mürtz

Lauterbach

et al. 2001

Israel Journal of Chemistry

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Cavity ring‐down spectroscopy (CRDS) is a highly sensitive laser absorption method. It can be used for quantitative analysis of molecular species at the sub‐ppb level. The absorption cell (cavity) is sealed by two high‐reflective mirrors on each side, which results in an effective absorption path‐length of some kilometers. Our experiments for atmospheric gas analysis have been carried out so far with an Excimer pumped dye laser in the UV‐VIS and a CO overtone sideband laser in the wavelength region around 3 μm. Experiments with an all solid‐state difference frequency laser system will follow. In the UV‐VIS region, we measured trace gas molecules like SO2, NO2, and CH2O. In the mid‐infrared, around 3 μm, we measured hydrocarbons like CH4, C2H6, and C2H4 with a detection limit of less than 1 ppb. The noise equivalent absorption coefficients in the MIR are in the order of 1.7·10−9 cm−1. Due to the high data acquisition rate and the high sensitivity, CRDS enables real‐time detection of trace gases in ambient air.

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“…14 More recently, the potential of CRDS in the detection and spectroscopy of analytes in condensed samples has been realized. Recent developments include deposition of a thin film onto the mirror surfaces 18 , situating a thin film in the cavity perpendicular to the cavity axis, 19,20 at Brewster's angle, 21 or using a monolithic crystal [22][23][24][25] or a long optical waveguide loop [26][27][28][29] as a cavity to probe the absorption by the evanescent wave. Many of these techniques have been the subject of a recent review.…”

Section: Introductionmentioning

confidence: 99%

Absorption measurements in microfluidic devices using ring-down spectroscopy

et al. 2005

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When monitoring separation events in microfluidic devices, one frequently needs to detect small amounts of analyte in picolitre sized volumes with a time response of milliseconds. Fluorescence detection is typically the method of choice due to its very high sensitivity and fast response. However, since many analytes are not naturally fluorescent, labelling protocols may have to be introduced and thereby increase the complexity of the analysis. Here, we present an alternative method that is based on optical absorption, or more specifically on the ring-down time of an optical signal in a cavity or loop made of waveguide material. This optical decay constant changes as small liquid samples containing absorbing species are introduced into a fiber-optic loop. It is demonstrated that one can obtain the optical decay constant using a continuous wave laser beam that is intensity modulated and then coupled into an optical fiber loop. The inherent exponential decay in the fiber loop introduces a phase shift of the light emitted from the loop with respect to the pumping beam. By measuring this phase shift, one can readily determine the concentration of the analyte introduced between the two fiber ends and a model is established to describe the relationship. It is demonstrated that this technique, dubbed "phase-shift fiber-loop ring-down spectroscopy" (PS-FLRDS), is well suited as an absorption detector for any flow system in which the optical absorption path is limited by the instrument architecture.

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Cavity ring-down spectroscopy of molecularly thin iodine layers

Cited by 37 publications

References 0 publications

Optical Absorption Spectrum of Gold Atoms Deposited onSiO2from Cavity Ringdown Spectroscopy

Optical Absorption Spectrum of Gold Atoms Deposited onSiO2from Cavity Ringdown Spectroscopy

Atmospheric trace gas analysis with cavity ring‐down spectroscopy

Absorption measurements in microfluidic devices using ring-down spectroscopy

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