Bandwidth-Limited Picosecond Pulses from an Injection GaAlAs DH Laser with an External Dispersive Cavity

Mode locking of semiconductor lasers with external dispersive cavities is investigated both experimentally and theoretically. The external cavity consists of a microscope objective and a diffraction grating. Bandwidth-limited tunable picosecond pulses (FWHM about 3 ps and Δτ · Δυ= 0.30) are obtained with such a configuraton. The pulse duration is measured by a second-harmonic generation (SHG) correlation method and an ultrafast streak camera. Theoretical investigations of mode locking based on the time-domain approach and pulse propagation through the elements of the ring laser cavity are carried out. The laser medium is considered to be divided into two parts-the amplifying and absorbing regions. The steady state pulse parameters (duration, energy, and asymmetry) are derived from the computer simulation and are compared with the experiment. The effects of gain and absorber saturation are included in the treatment. Copyright © 1985 by The Institute of Electrical and Electronics Engineers, Inc

DIRECT DETECTION OF PICOSECOND PULSES EMITTED BY AN INJECTION LASER WITH ACTIVE MODE LOCKING.

An Agat-SF linear-scan streak image-converter camera was used to record output pulses of 2. 7 psec duration generated by an injection laser with an external dispersive resonator operated in the active mode-locking regime. The duration of the pulses was determined by the reciprocal of the spectral width and the product of the duration and the spectral width was 0. 30

Subpicosecond Pulse Generation by a Tandem-Type AlGaAs DH Laser with Colliding Pulse Mode Locking

Experimental results of colliding pulse mode locking (CPM) of a double-contact AlGaAs DH injection laser with an external cavity are presented. The laser has two amplifying sections and a passive umpumped segment located between them which exhibited saturable absorption action. Ultrashort pulses propagating in opposite directions collided in the absorber and pulse shortening occurred. Bursts of 0.8 ps IFWHM) pulses at a 710 MHz repetition rate are obtained by means of CPM. The pulse duration is measured by a second harmonic generation correlation method and an ultra fast streak camera. Copyright © 1986 by The Institute of Electrical and Electronics Engineers, Inc

GENERATION OF PICOSECOND PULSES IN AN INJECTION LASER WITH AN EXTERNAL SELECTIVE RESONATOR.

Pulses of 15 psec duration were generated by an injection laser with an external dispersive resonator operating in the active mode-locking regime. This regime was attained by subjecting the laser diode to a current of high frequency equal to the intermode interval in the external resonator. The duration of the pulses was determined by an autocorrelation method in which the second harmonic was generated in an LiIO//3 crystal

Coherent Light Sources under strong field-matter coupling in an optically dense resonant medium without population inversion

A new approach in the development of coherent radiation sources has been studied both theoretically and experimentally. The approach is based on the parametric excitation of collective modes of the field + matter system in two-level resonant optically dense media with strong coupling between the field and matter. Copyright © 2005 by Astro, Ltd

Ceruloplasmin: Macromolecular Assemblies with Iron-Containing Acute Phase Proteins

Copper-containing ferroxidase ceruloplasmin (Cp) forms binary and ternary complexes with cationic proteins lactoferrin (Lf) and myeloperoxidase (Mpo) during inflammation. We present an X-ray crystal structure of a 2Cp-Mpo complex at 4.7 A resolution. This structure allows one to identify major protein-protein interaction areas and provides an explanation for a competitive inhibition of Mpo by Cp and for the activation of p-phenylenediamine oxidation by Mpo. Small angle X-ray scattering was employed to construct low-resolution models of the Cp-Lf complex and, for the first time, of the ternary 2Cp-2Lf-Mpo complex in solution. The SAXS-based model of Cp-Lf supports the predicted 1ratio1 stoichiometry of the complex and demonstrates that both lobes of Lf contact domains 1 and 6 of Cp. The 2Cp-2Lf-Mpo SAXS model reveals the absence of interaction between Mpo and Lf in the ternary complex, so Cp can serve as a mediator of protein interactions in complex architecture. Mpo protects antioxidant properties of Cp by isolating its sensitive loop from proteases. The latter is important for incorporation of Fe(3+) into Lf, which activates ferroxidase activity of Cp and precludes oxidation of Cp substrates. Our models provide the structural basis for possible regulatory role of these complexes in preventing iron-induced oxidative damage