Physics and Applications of Laser Diode Chaos

An overview of chaos in laser diodes is provided which surveys experimental achievements in the area and explains the theory behind the phenomenon. The fundamental physics underpinning this behaviour and also the opportunities for harnessing laser diode chaos for potential applications are discussed. The availability and ease of operation of laser diodes, in a wide range of configurations, make them a convenient test-bed for exploring basic aspects of nonlinear and chaotic dynamics. It also makes them attractive for practical tasks, such as chaos-based secure communications and random number generation. Avenues for future research and development of chaotic laser diodes are also identified.Comment: Published in Nature Photonic

Clarification of the GaP(001)(2x4) Ga-rich reconstruction by scanning tunneling microscopy and ab initio theory

We infer the structure of the GaP(001)(2x4) surface from a study of scanning tunneling microscopy (STM) images obtained under UHV conditions on metal-organic vapor phase epitaxy grown samples. STM images are compared with results of first-principles calculations for models energetically most favorable under Ga-rich growth conditions. The comparison shows that the GaP(001)(2x4) surface unit cell consists of a mixed Ga-P dimer on top of a complete gallium layer, hence ruling out the Cia-Ga dimer model

Semiisolierende VCZ GaAs - Einkristalle Schlussbericht

1. The rapid development of GaAs technology for microwave electronics requires semiinsulating crystals of large diameters with remaining or reduced defect densities. Mostly, they are grown by the LEC method. The dislocation density is relatively high and lies in 4- and 6-inch crystals at about (0.5-1.5) x 10"5 cm"-"2. 2. In order to reduce the dislocation density and their inhomogeneous distribution, the crystals have to be grown in homogensised temperature fields, meaning in first approximation: lowering of the temperature gradients (25-30 K/cm). 3. For that the pulling method was modified. Now, the crystals grows in an additiona, thermally insulated inner chamber with controlled arsenic atmosphere (vapour pressure controlled Czochralski method: VCZ). 4. Compared to LEC crystals, 4-inch VCZ crystals show markedly reduced dislocation density of (3-5) x 10"3 cm"-"2 and very small residual stresses. 5. VCZ wafers were tested by a standard epitaxy process and were proofed to be suitable for device production. Thus, in agreement with the industrial partner a continuation of the research was agreed for the development of a 6 inch VCZ-technology aimed to be transferred to production. (orig.)Available from TIB Hannover: F99B24+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman