ABSTRACT
The technology of hot-pressed Cr(2+):ZnSe ceramic preparation is reported. Comparative gain-switched lasing of hot-pressed ceramic and CVD grown Cr(2+):ZnSe samples with slope efficiencies up to 10% and output energies up to 2 mJ were demonstrated. This is a milestone in the development of future large scale mid-IR laser systems based on ceramic TM(2+):II-VI materials. This evolving technology has excellent potential as media for practical low cost, high power mid-IR laser applications.
ABSTRACT
We report a room temperature Fe:ZnSe laser in gain-switched operation and tuning over the 3.9 - 4.8microm spectral range. Mid-IR emission of Fe2+:ZnSe was studied under three regimes of excitation: ordinary optical (2.92mum) excitation of 5T2 excited state of Fe2+; excitation via 5E level of Cr co-dopant (1.56mum); and excitation via photo-ionization transition of Fe2+ (0.532mum). The energy transfer from Cr2+ (5E level) to Fe2+ (5T2 level) under 1.56microm wavelength excitation was observed and resulted in simultaneous RT emission of Fe:Cr:ZnSe crystal over ultra-broadband spectral range of 2- 3 and 3.5-5mum. We also report the observation of mid-IR emission at 3.5- 5mum induced by 2+->3+->2+ ionization transitions of the iron ions in Fe:ZnSe.
ABSTRACT
The association of appendicitis with schistosomiasis in the appendix is extremely rare in France. We report herein a new case in which the diagnosis was made, in the presence of pseudo-tumoral appendicitis, by frozen section biopsies. The patient presented with a typical acute appendicitis, without urinary symptoms, and with granulocytosis (14000 white cells/mm3, without eosinophilia). At laparotomy, the appendix was voluminous, with necrotic abscess, and lymph node masses were noted on the greater omentum. Frozen section biopsies of an omental tumor showed schistosoma eggs, without malignant cells. Appendicectomy and partial omentectomy were performed. Postoperative course was uneventful. Pathologic examination of the resected specimen showed schistosoma eggs in all layers of the appendix, and in the omentum. Final diagnosis was established by positive serology and by findings Schistosoma haematobium eggs in the urine. The patient was treated postoperatively by praziquantel. In conclusion, in case of acute appendicitis, with pseudotumorous appendix and lymph node masses, even with poor epidemiological findings on the clinical history, frozen section biopsies can sometimes establish the diagnosis of schistosomiasis with appendicitis, and avoid unjustified bowel resection.