Performance comparison of Yb:YAG ceramics and crystal gain material in a large-area, high-energy, high average-power diode-pumped laser.

We compare for the first time the influence of different Yb:YAG gain media on the performance of a large-area, high average-power laser system with an output energy of up to 6 J. Monocrystalline slabs grown by a new technique without central growth defect are compared with ceramics. Small signal gain, maximum output energy and thermal lensing are compared for ceramic slabs with co-sintered amplified spontaneous emission (ASE) absorber cladding, monocrystalline slab with and without optically bonded ASE absorber cladding, and surface structured monocrystalline slabs.

Multicolour photochromic response of Ag-TiO2 nanocomposite--role of light illumination.

Multicolour photochromism of Ag-TiO2 nanocomposite material was found several years ago but its microscopic origin is still ambiguous. We study the initial stages of the effect of light exposure on extinction spectrum of this material prepared by photocatalytic technique. We propose a simple model to analyse the experimental data that suggests that the extinction changes are due to a pure shift of the plasmon resonance of silver nanoparticles after light exposure.

Laser-induced refractive index changes in nanocrystalline diamond membranes.

We have observed what we believe to be a new phenomenon in nanocrystalline diamond membranes. The optical thickness of the membrane is changed under laser irradiation, which leads to a spectral shift of interference fringes in the transmission and photoluminescence spectra of high-quality thin self-supporting nanocrystalline membranes. The direction of the spectral shift (red/blue) can be tuned by the ambient air pressure.