ABSTRACT
We used COMSOL Multiphysics to design a prototype actively cooled "flow-cell" substrate targeted at high-average-power applications, fabricated the prototype from cordierite ceramic, and tested the substrate under load in our thermal loading test stand. Sub-aperture testing revealed average-power handling up to 3.88-W/cm2 absorbed power density, in excellent agreement with model predictions. Gratings fabricated on 2-in.-diam cordierite coupons were subjected to laser-damage testing and showed a damage threshold of 250 mJ/cm2.
ABSTRACT
We report the compression of intense, carrier-envelope phase stable mid-IR pulses down to few-cycle duration using an optical filament. A filament in xenon gas is formed by using self-phase stabilized 330 microJ 55 fs pulses at 2 microm produced via difference-frequency generation in a Ti:sapphire-pumped optical parametric amplifier. The ultrabroadband 2 microm carrier-wavelength output is self-compressed below 3 optical cycles and has a 270 microJ pulse energy. The self-locked phase offset of the 2 microm difference-frequency field is preserved after filamentation. This is to our knowledge the first experimental realization of pulse compression in optical filaments at mid-IR wavelengths (lambda>0.8 microm).
ABSTRACT
A non-suppurative encephalitis accompanied by intraneuronal intranuclear inclusions were observed in the brain from a cow that died within 10 hours of developing nervous signs. Immunogold-silver staining located Aujeszky's disease virus antigen in neuronal cytoplasm and the virus was isolated from large volumes of suspensions of nervous tissues and tonsils. Fattening pigs in adjacent buildings had high antibody titres to Aujeszky's disease virus. The methods by which the cow could have acquired infection are considered, and the significance of transient low titres of antibodies to Aujeszky's disease virus in in-contact cows is discussed.
