Sökning: "frequency-modulation spectroscopy"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden frequency-modulation spectroscopy.

  1. 1. Diode laser spectroscopy in extended wavelength ranges

    Författare :Ulf Gustafsson; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diode-laser spectroscopy; frequency-modulation spectroscopy; frequency conversion; fluorescence spectroscopy; scattering; diffraction; Fysicumarkivet A:2000:Gustafsson; Atomic and molecular physics; Atom- och molekylärfysik; absorption spectroscopy;

    Sammanfattning : Diode laser spectroscopy performed in the ultraviolet, visible and infrared spectral regions is presented. The accessible wavelength range for visible and near-infrared diode lasers is extended by the use of sum- and difference-frequency generation. LÄS MER

  3. 2. Near-infrared gas analysis spectroscopy systems with semiconductor lasers

    Författare :Lars Sandström; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; carbon dioxide; semiconductor lasers; wavelength modulation spectroscopy; NIR spectroscopy; Ammonia; frequency modulation spectroscopy; optical fiber; gas detection;

    Sammanfattning : .... LÄS MER

  4. 3. Environmental Monitoring - using diode-laser-based spectroscopic techniques

    Författare :Gabriel Somesfalean; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Diode-laser spectroscopy; frequency-modulation spectroscopy; frequency conversion; diffraction; scattering; Electromagnetism; acoustics; akustik; optik; absorption spectroscopy; Elektromagnetism; optics; Fysicumarkivet A:2004:Somesfalean;

    Sammanfattning : Monitoring of environmental gases is necessary to understand the complex processes governing global warming and the impact of pollutant emissions related to human activity. Diode-laser-based spectroscopic techniques, being robust and affordable, have a great potential to become an industrially well-established technology for environmental sensing. LÄS MER

  5. 4. Further development of NICE-OHMS : – an ultra-sensitive frequency-modulated cavity-enhanced laser-based spectroscopic
 technique for detection of molecules in gas phase

    Författare :Patrick Ehlers; Ove Axner; Joakim Bood; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NICE-OHMS; Frequency Modulation; Cavity Enhancement; Molecular Spectroscopy; fysik; Physics;

    Sammanfattning : Noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, NICE-OHMS, is a laser-based spectroscopic detection technique that comprises the concepts of frequency modulation (FM, for reduction of 1/f-noise by detecting the signal at a high frequency) and cavity enhancement (CE, for a prolongation of the optical path length) in a unique way. Properly designed, this gives the technique an intrinsic immunity against the frequency-to-noise conversion that limits many other types of CE techniques. LÄS MER

  7. 5. Fiber-laser-based noise-immune cavity-enhanced optical heterodyne molecular spectrometry

    Författare :Aleksandra Foltynowicz; Ove Axner; Weidong Chen; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; absorption spectrometry; frequency modulation; cavity enhancement; NICE-OHMS; Laser frequency stabilization; fiber laser; Fabry-Perot cavities; sub-Doppler spectroscopy; trace gas detection; Physics; Fysik; Molecular physics; Molekylfysik; fysik; Physics;

    Sammanfattning : Noise-immune cavity-enhanced optical heterodyne molecular spectro-metry (NICE-OHMS) is one of the most sensitive laser-based absorption techniques. The high sensitivity of NICE-OHMS is obtained by a unique combination of cavity enhancement (for increased interaction length with a sample) with frequency modulation spectrometry (for reduction of noise). LÄS MER