Free-space and underwater GHz data transmission using AlGaInN laser diode technology

Laser diodes fabricated from the AlGaInN material system is an emerging technology for defence and security applications; in particular for free space laser communication. Conventional underwater communication is done acoustically with very slow data rates, short reach, and vulnurable for interception. AlGaInN blue-green laser diode technology allows the possibility of both airbourne links and underwater telecom that operate at very fast data rates (GHz), long reach (100’s of metres underwater) and can also be quantum encrypted. The latest developments in AlGaInN laser diode technology are reviewed for defence and security applications. The AlGaInN material system allows for laser diodes to be fabricated over a very wide range of wavelengths from u.v., ~380nm, to the visible ~530nm, by tuning the indium content of the laser GaInN quantum well. Ridge waveguide laser diode structures are fabricated to achieve single mode operation with optical powers of <100mW. Visible light communications at high frequency (up to 2.5 Gbit/s) using a directly modulated 422nm Galliumnitride (GaN) blue laser diode is reported in free-space and underwate

Photoluminescence studies of a perceived white light emission from a monolithic InGaN/GaN quantum well structure

In this work we demonstrate by photoluminescence studies white light emission from a monolithic InGaN/GaN single quantum well structure grown by metal organic chemical vapour deposition. As-grown and thermally annealed samples at high temperature (1000 °C, 1100 °C and 1200 °C) and high pressure (1.1 GPa) were analysed by spectroscopic techniques, and the annealing effect on the photoluminescence is deeply explored. Under laser excitation of 3.8 eV at room temperature, the as-grown structure exhibits two main emission bands: a yellow band peaked at 2.14 eV and a blue band peaked at 2.8 eV resulting in white light perception. Interestingly, the stability of the white light is preserved after annealing at the lowest temperature (1000 °C), but suppressed for higher temperatures due to a deterioration of the blue quantum well emission. Moreover, the control of the yellow/blue bands intensity ratio, responsible for the white colour coordinate temperatures, could be achieved after annealing at 1000 °C. The room temperature white emission is studied as a function of incident power density, and the correlated colour temperature values are found to be in the warm white range: 3260–4000 K

Anti-inflammatory plasma cytokines in children and adolescents with Down syndrome.

Cytokines participate in many physiological processes including the regulation of immune and inflammatory responses. Production of some important cytokines in children with Down syndrome (DS) is depressed or increased. In this study we analysed the selected anti- inflammatory cytokines: interleukin-4 (IL-4), interleukin-10 (IL-10), interleukin-13 (IL-13) in plasma of children and adolescents with DS. The study group consisted of 20 patients with Down syndrome and 33 healthy subjects at the age of 5-17 years. Levels of: IL-4, IL-10 and IL-13 in plasma samples were determined by specific enzyme- linked immunosorbent assay (ELISA) techniques according to manufacturer's instructions. IL-4 was detectable in 25% subjects with Down syndrome and in 28.6% healthy subjects. IL-13 was detectable in 15% patients with Down syndrome and in 15.2% healthy subjects, respectively. IL-10 was detectable in 1 of 20 patients with Down syndrome and in 2 of 33 healthy subjects only. No significant correlations between measurable cytokine levels and age and gender were found. No significant increased concentration of selected anti- inflammatory cytokines were detected

On BF-perfect graphs

SIGLETIB: RO 1829 (1985,34) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Blue Laser on High N2\text{}_{2} Pressure-Grown Bulk GaN

In this note we report briefly on the details of pulsed-current operated "blue" laser diode, constructed in our laboratories, which utilizes bulk GaN substrate. As described in Ref. [1] the substrate GaN crystal was grown by HNPSG method, and the laser structure was deposited on the conducting substrate by MOCVD techniques (for the details see Sec. 2 and Sec. 4 of Ref.~[1], respectively)