Browsing by Subject "Optical saturation"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Multimode pumping of optical parametric oscillators
    (Institute of Electrical and Electronics Engineers, 1996-02) Marshall, L. R.; Kaz, A.; Aytur, O.
    Calculations suggest that optical parametric oscillators (OPO's) can be efficiently pumped using multimode, divergent pump sources. The influence of pump beam divergence and mode structure upon OPO performance is measured for both noncritical phase-matching, and OPO's with walkoff. Multimode OPO pumping is shown to be efficient, provided appropriate nonlinear crystals and OPO cavities are employed; the nonlinear crystal must have sufficient angular acceptance to tolerate a divergent pump; the OPO cavity must support modes that match the divergence and spatial intensity characteristics of the pump, For low-order pump modes, the OPO can be made to match the mode of the pump. Higher order pump modes reduce the OPO efficiency, and cause a saturation of efficiency with increasing pump power. The efficiency is degraded in a similar fashion in the presence of walkoff. Multimode pumping is more difficult in longer OPO cavities due to increased buildup time of higher order OPO modes.
  • Thumbnail Image
    ItemOpen Access
    Size effect in optical activation of TiO2 nanoparticles in photocatalytic process
    (IEEE, 2007) Soğancı, İbrahim Murat; Mutlugün, Evren; Tek, Sümeyra; Demir, Hilmi Volkan; Yücel, D.; Çeliker, G.
    In this work, we optically investigate and characterize the photocatalytic recovery of contaminated TiO 2 nanoparticles of different sizes that are incorporated in solgel films to study the size effect. We demonstrate significant improvement in the optical efficiency of the photocatalytic nanoparticles as we reduce the particle size.