Publications in Scientific Journals:
A. Ajami, W. Husinsky, B. Svekova, S. Vytykacova, P. Nekvindova:
"Saturable absorption of silver nanoparticles in glass for femtosecond laser pulses at 400 nm";
Journal of Non-Crystalline Solids,
The commercially available glass BK7 was chosen to prepare silver-rich layer within the glass by the silver (Ag)
ion exchange method in order to enhance its nonlinear optical properties. The glass substrates were doped with
Ag at 320 °C by a 50-minute Ag+↔Na+ion exchange in a melt of NaNO3 and KNO3 containing 14 mol% of AgNO3.
Then, one piece of glass BK7 containing Ag ions (as-exchanged sample) was annealed in air for 1 h at 600 °C to
prepare the as-annealed sample. The thickness of the layer containing Ag in the as-exchanged glass BK7 was
measured to less than 1 μm. It was found that during the post-exchanged annealing most silver diffused deeply
into the glass substrate leading to increase the thickness of the layer to 110 μm. However, some amount of Ag nucleated
during the annealing, thus creating small nanoparticles (NPs) with an average size of 2nm. The linear and
nonlinear optical properties of the as-exchanged and as-annealed glass BK7 were studied. The as-exchanged
sample showed no absorption in the visible spectral region whereas, as-annealed glass BK7 showed a peak absorption
at 420 nm which can be attributed to the presence of Ag NPs formed in this glass. The nonlinear optical
behavior of the samples was investigated using 800 nm and 400 nm femtosecond pulses. Strong saturable absorptionwas
observed in the as-annealed sample at 400 nm. This feature promises an efficientway for designing
all optical switching devices appropriate for the second harmonic of the Ti-sapphire laser. Using nonlinear transmission
(NLT) method the saturation intensity for the as-annealed sample was determined 8.5 × 1011 W·cm−2.
An intensity dependent switching from saturable absorption (SA) to reverse saturable absorption (RSA)was also
observed when the as-annealed sample was irradiated simultaneously by 800 nm and 400 nm femtosecond
Saturable absorption; Nanoparticles; Glass-metal composite; Nonlinear optical properties
Created from the Publication Database of the Vienna University of Technology.