Passive mode-locking in semiconductor lasers with saturable absorbers bandgap shifted through quantum well intermixing

Passive mode-locking in semiconductor lasers in a Fabry–Perot configuration with a bandgap blueshift applied to the saturable absorber (SA) section has been experimentally characterized. For the first time a fully post-growth technique, quantum well intermixing, was adopted to modify the material bandgap in the SA section. The measurements showed not only an expected narrowing of the pulse width but also a significant expansion of the range of bias conditions generating a stable train of optical pulses. Moreover, the pulses from lasers with bandgap shifted absorbers presented reduced chirp and increased peak power with respect to the nonshifted case

MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment

Liquid Argon Time Projection Chamber detectors are well suited to study neutrino interactions, and are an intriguing option for future massive detectors capable of measuring the parameters that characterize neutrino oscillations. These detectors combine fine-grained tracking with calorimetry, allowing for excellent imaging and particle identification ability. In this talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be presented. The ability of MicroBooNE to differentiate electrons from photons gives the experiment unique capabilities in low energy neutrino interaction measurements.Comment: Proceedings of the 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09

First Measurement of Muon Neutrino Charged Current Quasielastic (CCQE) Double Differential Cross Section

Using a high statistics sample of muon neutrino charged current quasielastic (CCQE) events, we report the first measurement of the double differential cross section as a function of muon energy and angle for this process. The result features reduced model dependence and supplies the most complete information on neutrino CCQE scattering to date. Measurements of the absolute cross section as a function of neutrino energy and the single differential cross section as a function of 4-momentum transfer squared are also provided, largely to facilitate comparison with prior measurements. This data is of particular use for understanding the axial-vector form factor of the nucleon as well as improving the simulation of low energy neutrino interactions on nuclear targets, which is of particular relevance for experiments searching for neutrino oscillations.Comment: 6 pages, 6 figures, Proceedings of the 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09

Challenges in Extracting Charged Current Quasi-Elastic Model Information in MiniBooNE's Anti-Neutrino Data

Using a high-statistics sample of anti-neutrino charged current quasi-elastic (CCQE) events, MiniBooNE reports the challenges in measuring parameters within the Relativistic Fermi Gas model. As the CCQE analysis has been completed in MiniBooNE's neutrino data, particular attention is paid to the differences in CCQE interactions between the two running modes.Comment: NuInt '09 conference proceedings. Four pages, five figure

High-extinction-ratio TE/TM selective Bragg grating filters on silicon-on-insulator

We report on the design and fabrication of TE and TM polarization selective Bragg grating filters in the form of sinusoidal perturbations on the waveguide sidewall and etched holes on the top of the waveguide, respectively. Combining the two geometries on a silicon-on-insulator waveguide resulted in Bragg grating filters with high extinction ratios of approximately 60 dB

PCAC and coherent pion production by neutrinos

Coherent pion production in low energy neutrino reactions is discussed in the framework of the partially conserved axial vector current theory (PCAC). The role of lepton mass effects in suppressing production of positively charged pions is discussed. Instead of using models of pion nucleus scattering, the available data on pion carbon scattering are implemented for an analysis of the PCAC prediction. Our results agree well with the published upper limits for positively charged production but are much below the recent MiniBooNE result for neutral pion production.Comment: 6 pages, 7 figures, writeup of talk presented at NUINT 200