title: Laser-induced refractive index changes in nanocrystalline diamond membranes.
abstract: 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. The effect is reversible and is accompanied by changes in photoluminescence intensity. We interpret the results in terms of the changes in the index of refraction caused by the photoinduced adsorption/desorption of air molecules that subsequently affect the properties of subgap energy states related to the surface and the grain boundaries of the nanocrystals.
authors.affiliation: Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 121 16 Prague 2, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Preclíková
authors.forename: Alexander
authors.initials: A
authors.lastname: Kromka
authors.forename: Bohuslav
authors.initials: B
authors.lastname: Rezek
authors.forename: Petr
authors.initials: P
authors.lastname: Malý
mesh_terms: D018130:Diamond / Q000737:chemistry*; D007834:Lasers; D008567:Membranes, Artificial; D053758:Nanoparticles / Q000737:chemistry*; D055620:Optical Phenomena; D011312:Pressure; D013696:Temperature
chemical_list: D008567:Membranes, Artificial; D018130:Diamond