Alexander A Kachanov

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We describe the use of liquid-phase continuous-wave cavity ring-down spectroscopy for the detection of an HPLC separation. This technique builds on earlier work by Snyder and Zare using pulsed laser sources and improves upon commercially available UV-visible detectors by a factor of up to 50. The system employs a compact doubled-diode single-mode(More)
A collinear-beam thermal lens detector has been constructed and its properties were characterized. Its application to the high-performance liquid chromatography (HPLC) separation of a mixture of five anthraquinone dyes dissolved in water shows a linear response over 3.5 orders of magnitude and a detection limit that is subnanomolar in the dye(More)
We study the response of a high-finesse optical cavity to a cw laser during the laser frequency passage through resonance. For a laser that is spectraly larger than the cavity resonance, laser-field phase fluctuations are converted into amplitude fluctuations, and cavity injection is intrinsically noisy. We develop a model based on Schawlow-Townes(More)
Recent measurements of carbon isotopes in carbon dioxide using near-infrared, diode-laser-based cavity ring-down spectroscopy (CRDS) are presented. The CRDS system achieved good precision, often better than 0.2 per thousand, for 4% CO2 concentrations, and also achieved 0.15-0.25 per thousand precision in a 78 min measurement time with cryotrap-based(More)
We report the demonstration of high-sensitivity intracavity laser absorption spectroscopy with multiple-quantum-well vertical-external-cavity surface-emitting semiconductor lasers (VECSEL's). A detection limit of 3 x 10(-10) cm (-1) has been achieved. The spectrotemporal dynamics of a VECSEL in the 1030-nm wavelength region has been studied. The laser was(More)
Spectra composed of hundreds of time components for absorption path lengths of up to 130 km have been recorded near 1050 nm by combination of two recent techniques, intracavity laser spectroscopy with vertical external cavity surface-emitting multiple-quantum-well lasers and time-resolved Fourier transform spectroscopy. A sensitivity of 1 x 10(-10) cm(-1)(More)
Thermal lensing (TL) permits ultra-sensitive measurements of optical absorption of analytes in very small liquid volumes. We report the construction and use of a TL detector based on pulsed ultraviolet (UV) laser excitation (266 nm). We applied this detector to quantitate amino acids using capillary electrophoresis (CE) as a means of separation. Sixteen(More)
High fluences inside cavity ring-down spectroscopy optical resonators lend themselves to fluorescence or Raman spectroscopy. An instrument at 488 nm was developed to measure extinction, and fluorescence of aerosols. A detection limit of 6 x 10;-9 cm;-1Hz;-1/2 (0.6 Mm;-1Hz;-1/2) was achieved. The fluorescence spectral power collected from a single(More)
Intracavity laser absorption spectroscopy with ultrahigh sensitivity and enhanced spectral resolution is demonstrated. It entails use of an intracavity étalon that selects equally spaced modes of the cavity. These modes are reduced in intensity when they occur at spectral locations where absorption that is due to intracavity species also occurs. We obtained(More)