Generation of sub-10-fs pulses from a Kerr-lens mode-locked Cr(3+):LiCAF laser oscillator by use of third-order dispersion-compensating double-chirped mirrors

Pulses as short as 9 fs at 220-mW average power and a 97-MHz repetition rate are generated from a cw Ti:sapphire-pumped Kerr-lens mode-locked Cr(3+)LiCAF laser oscillator employing broadband double-chirped mirrors for second- and third-order dispersion compensation. Fine adjustment of dispersion is accomplished with a fused-silica prism pair. The result demonstrates that Raman-induced self-frequency shifting of the pulse does not limit sub-10-fs pulse generation from colquiriite crystals.     

Phosphorescent Platinum(II) Complexes with C^C* Cyclometalated NHC Dibenzofuranyl Ligands: Impact of Different Binding Modes on the Decay Time of the Excited State

Two C^C* cyclometalated platinum(II) N‐heterocyclic carbene (NHC) complexes with the general formula [(C^C*)Pt(O^O)] (C^C*=1‐dibenzofuranyl‐3‐methylbenzimidazolylidene; O^O=dimesitoylmethane) have been synthesized and extensively characterized, including solid‐state structure determination, ¹⁹⁵Pt NMR spectroscopy, and 2D NMR (COSY, HSQC, HMBC, NOESY) spectroscopy to elucidate the impact of their structural differences. The two regioisomers differ in the way the dibenzofuranyl (DBF) moiety of the NHC ligand is bound to the metal center, which induces significant changes in their physicochemical properties, especially on the decay time of the excited state. Quantum yields of over 80 % and blue emission colors were measured.     

Study of DyFe12−xMx compounds by57Fe and161Dy Mössbauer spectroscopy

DyFe_12?xM_x (M=Si,Ti,Cr) were studied with⁵⁷Fe and¹⁶¹Dy Mössbauer spectroscopy. The deduced coupling constants J_RFe of these compounds are about equal. It is found that Si is substituting one particular Fe-site, while Cr is substituting Fe randomly. In DyFe₁₀Si₂ two Fe-sites favour a c-axis anisotropy, while the third one favours the basal plane.     

A steepest-descent method for the calculation of localized orbitals and pseudoorbitals

A method for direct calculation of localized non-orthogonal orbitals, which has been proposed by the authors recently, is extended to cases where the overlap between different subsystems is very large. This is achieved by using a steepest-descent procedure. In addition, a computationally simple treatment of correlation effects is introduced into the method by means of the density functional formalism. Results of the method are given for e.g. LiH, CH₄, Ne₂, CO,(FH)₂.     

Flux line lattice symmetries in the borocarbide superconductor LuNi2B2C

We compare the results of small angle neutron scattering on the flux line lattice (FLL) obtained in the borocarbide superconductor LuNi₂B₂C with the applied field along the c- and a-axes. For H‖c the temperature dependence of the FLL structural phase transition from square to hexagonal symmetry was investigated. Above 10 K the transition onset field. H ₂(T), rises sharply, bending away from H _c2(T) in contradiction to theoretical predictions of the two merging. For H‖a a first order FLL reorientation transition is observed at H _tr=3–3.5 kOe. Below H _tr the FLL nearest neighbor direction is parallel to the b-axis, and above H _tr to the c-axis. This transition cannot be explained using nonlocal corrections to the London model.     

Diode-pumped 10-fs Cr3+:LiCAF laser

We demonstrate 10-fs pulses from a diode-pumped, soft-aperture Kerr lens mode-locked Cr3+:LiCAF laser with a spectral bandwidth of 150 nm and 40 mW of output power at a repetition rate of 110 MHz. For dispersion compensation, double-chirped mirrors and prisms are used. The pulses are characterized by use of spectral shearing interferometry.