Lasing in cuprous iodide microwires

We report on the observation of lasing in cuprous iodide (CuI) microwires. A vapor-phase transport growth procedure was used to synthesize CuI microwires with low defect concentration. The crystal structure of single microwires was determined to be of zincblende-type. The high optical quality of single microwires is indicated by the observed series of excitonic emission lines as well as by the formation of gain under optical excitation. Lasing of triangular whispering-gallery modes in single microwires is demonstrated for fs- and ns-excitation from cryogenic temperatures up to 200 K. Timeresolved micro-photoluminescence studies reveal the dynamics of the laser process on the time scale of several picoseconds

A sequence based SNP approach for non-culture strain characterisation of Neisseria meningitidis

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Near-band-gap CuPt-order-induced birefringence in Al\u3csub\u3e0.48\u3c/sub\u3eGa\u3csub\u3e0.52\u3c/sub\u3eInP\u3csub\u3e2\u3c/sub\u3e

The order-induced birefringence in the near-band-gap spectral range (0.75 to 2.5 eV), and its dependence on the degree of ordering η is reported for Al0.48Ga0.52InP2. Transmission and reflection generalized variable angle spectroscopic ellipsometry, dark-field spectroscopy, and cross-polarized reflectance difference spectroscopy (CRDS) are used to determine precisely the room-temperature dielectric functions for polarization parallel and perpendicular to the ordering direction of a series of spontaneously CuPt-ordered samples grown by metalorganic vapor-phase epitaxy. The CRDS technique is introduced as an approach to sense extremely weak anisotropy at oblique angles of incidence. The observed order birefringence is treated as “chemical-stress” induced piezobirefringence. The dielectric function model for piezobirefringence in zinc-blende compounds, and selection rules for the transitions from the Γ4.5ν , Γ6(1) ν , Γ6(2) ν valence band states to the Γ6c conduction band states, allow excellent modeling of the order birefringence in the near-band-gap spectral region. Thus, explicit treatment of the transition-matrix k dependence, as recently suggested for ordered GaInP2 or GaInAs2, can be avoided. The transition energies, strengths, and broadening parameters for the three zone-center transitions are obtained from analysis of the sample dielectric function tensor. All parameters in the quasicubic perturbation model can be fitted. We find, in excellent agreement with recent theoretical predictions, that the spin-orbit splitting parameter of 76 meV is nearly ordering independent, and that the ratio of the crystal-field splitting to the band-gap reduction for the perfectly ordered alloy amounts to 0.62. The band gap of the disordered compound is extrapolated to 2.195 eV

Spectral Investigation of Laser Structures using NSOM Experiment

We present for the first time the local spectral analysis of quantum well laser devices recorded in the near-field region. The distribution of mode spectra along and active region was scanned near-field scanning optical miecroscopy (NSOM). This experimental technique in combination with the near-field analysis of optical field could be effective optical tool for the final diagnostic of optical waveguide and laser device.<br /

Optical properties of AgxCu1–xI alloy thin films

We report on the excitonic transition energy E0 and spin–orbit split-off energy Δ0 of γ-AgxCu1–xI alloy thin films studied by using reflectivity measurements at temperatures between 20 K and 290 K. The observed bowing behavior of the E0 transition as a function of the alloy composition is explained based on first-principles band structure calculations in terms of different physical and chemical contributions within the description of ordered alloys. The spin–orbit coupling is found to increase from a value of 640 meV for CuI to approximately 790 meV for AgI. Furthermore, we show that the temperature-dependent bandgap shift between 20 K and 290 K decreases with increasing Ag-content from 25 meV for CuI to 6 meV for AgI. We attribute this behavior mostly to changes in the contribution of thermal lattice expansion to the bandgap shift

Lasing in cuprous iodide microwires

We report on the observation of lasing in cuprous iodide (CuI) microwires. A vapor-phase transport growth procedure was used to synthesize CuI microwires with low defect concentration. The crystal structure of single microwires was determined to be of zincblende-type. The high optical quality of single microwires is indicated by the observed series of excitonic emission lines as well as by the formation of gain under optical excitation. Lasing of triangular whispering-gallery modes in single microwires is demonstrated for fs- and ns-excitation from cryogenic temperatures up to 200 K. Timeresolved micro-photoluminescence studies reveal the dynamics of the laser process on the time scale of several picoseconds

Lasing in cuprous iodide microwires

We report on the observation of lasing in cuprous iodide (CuI) microwires. A vapor-phase transport growth procedure was used to synthesize CuI microwires with low defect concentration. The crystal structure of single microwires was determined to be of zincblende-type. The high optical quality of single microwires is indicated by the observed series of excitonic emission lines as well as by the formation of gain under optical excitation. Lasing of triangular whispering-gallery modes in single microwires is demonstrated for fs- and ns-excitation from cryogenic temperatures up to 200 K. Timeresolved micro-photoluminescence studies reveal the dynamics of the laser process on the time scale of several picoseconds