In order to understand the physical processes associated with fs-laser waveguide writing in glass, the effects of the laser repetition rate, the material composition and feature size were studied. The resulting material changes were observed by collecting Raman and fluorescence spectra with a confocal microscope. The guiding behavior of the waveguides was evaluated by measuring near field laser coupling profiles in combination with white light microscopy. Waveguides and Bragg gratings were fabricated in fused silica using pulse repetition rates from 1 kHz to 1 MHz and a wide range of scan speeds and pulse energies. Two types of fluorescence were detected in fused silica, depending on the fabrication conditions. Fluorescence from self trapped exciton (E{prime}{sub {delta}}) defects, centered at 550 nm, were dominant for conditions with low total doses, such as using a 1 kHz laser with a scan speed of 20 {micro}m/s and pulse energies less than 1 {micro}J. For higher doses a broad fluorescence band, centered at 650 nm, associated with non-bridging oxygen hole center (NBOHC) defects was observed. Far fewer NBOHC defects were formed with the 1 MHz laser than with the kHz lasers possibly due to annealing of the defects during writing. We also observed an …

This work presents several observables for the reactions γ<italic> p</italic> → <italic>K</italic><super>+</super>Λ and γ<italic> p</italic> → <italic>K</italic><super>+</super>Σ°. In addition to measuring differential cross sections, we have made first measurements of the double polarization observables <italic>C_x</italic> and <italic> C_z</italic>. <italic>C_x</italic> and <italic>C_z</italic> characterize the transfer of polarization from the incident photon to the produced hyperons. Data were obtained at Jefferson Lab using a circularly polarized photon beam at endpoint energies of 2.4, 2.9, and 3.1 GeV. Events were detected with the CLAS spectrometer. In the Λ channel, the cross sections support the recent observation of new resonant structure at <italic>W</italic> = 1900 MeV. Studies of the invariant cross section, <math> <f> <fr><nu>d<g>s</g></nu><de>dd</de></fr></f> </math> show scaling behavior suggesting that the production mechanism becomes <italic> t</italic>-channel dominated near threshold at forward kaon angles. The double polarization observables show that the recoiling Λ is almost maximally polarized along the direction of the incident photon from mid to forward kaon angles. While Σ<super>o</super> differential cross sections are of the same magnitude as the Λ differential cross sections, there is evidence of different physics dominating the production mechanism. The Σ° invariant cross sections do not show the same <italic>t</italic>-scaling behavior present in the Λ results. …