Sökning: "optical lineshape"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden optical lineshape.

  1. 1. Optical Frequency Comb Fourier Transform Spectroscopy

    Författare :Alexandra C. Johansson; Aleksandra Foltynowicz; Ove Axner; Jürgen Röpcke; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Optical frequency comb spectroscopy; Fourier transform; molecular absorption dispersion; fysik; Physics;

    Sammanfattning : Fourier transform spectroscopy (FTS) based on optical frequency combs is an excellent spectroscopic tool as it provides broadband molecular spectra with high spectral resolution and an absolutely calibrated frequency scale. Moreover, the equidistant comb mode structure enables efficient coupling of the comb to enhancement cavities, yielding high detection sensitivity. LÄS MER

  3. 2. Lineshape in Quantum Cascade Lasers - Temperature, Screening and Broadening

    Författare :Rikard Nelander; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum Cascade Lasers; quantum wells; spectral lineshape; Non-Equilibrium Green s Functions; screening; temperature dependence;

    Sammanfattning : This dissertation deals with the optical properties of Quantum Cascade Lasers (QCLs). Studies are performed using transport calculations employing the theory of Non-Equilibrium Green's Functions, and screening is studied within the Random Phase Approximation. Focus is put on the temperature dependent effects in THz QCLs. LÄS MER

  4. 3. Everything is imperfect: Studies on point defects in insulators

    Författare :Christopher Linderälv; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; boron nitride; band alignment; oxygen vacancies; insulator; optical lineshape; point defects; density functional theory; wide band gap oxides;

    Sammanfattning : Point defects can be detrimental or absolutely necessary for the performance of a material. Due to the implications defects have on a material, defects have been widely studied over the last century. LÄS MER

  5. 4. Diffuse Optical Spectroscopy and Imaging of Turbid Media

    Författare :Can Xu; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; upconverting nanoparticles; luminescence; fluorescence; inverse problem; diffuse reflection spectroscopy; biomedical optics; photon migration; biomedical imaging; gas spectroscopy; medical diagnostics; tomography; Fysicumarkivet A:2013:Xu;

    Sammanfattning : This thesis deals with optical spectroscopy and imaging of complex and strongly scattering turbid media. Focus is mainly placed on three topics, being i) diffuse optical spectroscopy of choroidal tumors, ii) gas spectroscopy in scattering materials using the GASMAS (gas in scattering media absorption spectroscopy) technique, and iii) luminescence diffuse optical imaging and tomography of tissues. 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