Crystal growth, spectroscopy and laser performances of Pr3+:Sr0.7La0.3Mg0.3Al11.7O19 (Pr:ASL).

We report on the crystal growth, spectroscopic properties and visible laser performances of Pr3+-doped Sr0.7La0.3Mg0.3Al11.7O19 (ASL). ASL crystals doped with 2 at.% and 4 at.% Pr3+ were grown by Czochralski method. The laser experiments were carried out in a plane-concave resonator under excitation at 486 nm, provided from a 2ω-OPSL. Efficient laser emission was obtained with an 8 mm long sample of Pr(2at.%):ASL. The maximum output power amounted to 267 mW, 52 mW, and 318 mW at an absorbed power of 1.2W for red, orange, and deep red emission, respectively.

Bulles buccales hemorragiques revelatrice d'une leucemie lymphoide chronique chez un adulte. A propos d'un cas

Les auteurs rapportent un cas de LLC chez un adulte de 60 ans révélé par des bulles buccales à contenu hémorragique. Ils situent la place et l'importance de l'interrogatoire dans le diagnostic de cette affection. Devant la présence de ces bulles il est licite de demander un hémogramme et un myélogramme qui feront le diagnostic de certitude de l'affection. la prise en charge doit être pluridisciplinaire et repose avant tout sur une bonne préparation du terrain en milieu africain afin d'éviter des complications à type d'anguillulose maligne liée à la chimiothérapie

Rehabitation faciale par les protheses maxillo-faciales au cours des tumeurs benignes de la mandibule

Pour montrer la nécessité de développer les techniques de prothèse maxillo-faciales pour réhabiliter les patients tant au plan morpho-fonctionnel que social dans nos pays en voie de développement, nous rapportons des cas de PSIM . Elle concernait l'exérèse tumorale suivit d'une reconstitution par une prothèse maxillofaciale.Les tumeurs bénignes répertoriées ayant occasionné une exérèse tumorale avec PSIM sont dominées par l'améloblastome avec une proportion de plus de 74 %. Les PSIM obtenues sont du type I (51, 85%), III (37.03%), II (7.45 %) et IV (3.71 %). Les techniques de réhabilitation maxillo-faciales utilisées ont été dans plus de 56 % des cas des endoprothèses

[Facial localizations of Buruli ulcers: two cases]. / Les localisations faciales de l'ulcère de Buruli: à propos de deux cas.

We report the first two published cases of a facial localization of Mycobacterium ulcerans ulcer (Buruli ulcer). M. ulcerans is the third most common mycobacteriosis, after leprosy and tuberculosis. Clinical manifestations involve large necrotic ulcerations with protruding edges, mainly localized on the limbs. Both of our patients, 9 and 45-year-old females, resided in endemic areas of Buruli ulcer in the Ivory Coast. The ulcers were located on the left zygomatic malar region in one patient and the submental region in the other. Treatment involved resection of the ulcer followed by total skin graft. Ulcer healing was observed after two months hospitalization in one patient. The other patient died.

Diode-pumped Yb:Sr(3)Y(BO(3))(3) femtosecond laser.

We have developed a diode-pumped Yb(3+)Sr(3)Y(BO(3))(3) (Yb:BOYS) laser generating 69-fs pulses, at a central wavelength of 1062 nm. This laser is mode locked by use of a semiconductor saturable-absorber mirror and emits 80 mW of average power at 113 MHz. This is, to our knowledge, the first mode-locked Yb:BOYS laser and the shortest duration obtained from an ytterbium laser with a crystalline host. The central wavelength can be tuned from 1051 to 1070 nm, for sub-100-fs pulses. We have also achieved an average power as high as 300 mW with pulse duration of 86 fs at 1068 nm.

Generation of 90-fs pulses from a mode-locked diode-pumped Yb(3+):Ca(4)GdO(BO(3))(3) laser.

A diode-pumped Yb>(3+):Ca(4)GdO(BO>(3))(3) (Yb:GdCOB) laser generating 90-fs pulses at a center wavelength of 1045 nm is demonstrated. This is, to our knowledge, the shortest pulse duration obtained from an ytterbium laser with a crystalline host. This laser is mode locked with a high-finesse semiconductor saturable-absorber mirror and emits 40 mW of average power at a repetition rate of 100 MHz.

Second-harmonic generation in He+-implanted gadolinium calcium oxoborate planar waveguides.

What is believed to be the first investigation of second-harmonic generation (SHG) in Ca(4)GdO (BO(3))(3) waveguides is reported. A planar waveguide was formed by 2-MeV-helium implantation. We cut the sample to achieve type I noncritical phase matching of an 823-nm fundamental wave for fundamental light propagating along the y axis and polarized along the z crystallophysic axis of the crystal. SHG was achieved with a relatively low pumping power of a cw Ti:sapphire laser. The results indicate that the nonlinearity of the material remains in the guiding region after ion implantation.

Efficient and tunable continuous-wave diode-pumped Yb3+:Ca4GdO(BO3)3 laser.

A Yb(3+):Ca(4)GdO(BO(3))(3) (Yb:GdCOB) crystal has been diode pumped for the first time to our knowledge. We obtained 47.5% slope efficiency at 6 degrees C, producing 191 mW of power at 1050 nm, with a 2.4% output coupler. Temperature does not significantly affect the laser performance: At room temperature we still obtained 180 mW of power for the same cavity. We achieved tunability of the Yb:GdCOB laser from 1035 to 1088 nm with a 1.7% output coupler and 100-nm tunability with a low-transmission output coupling (T = 0.03%).

Formation of planar optical waveguides in the new nonlinear gadolinium calcium oxoborate, Ca(4)GdO(BO(3))(3), crystal by 2-MeV He(+) implantation.

A planar waveguide composed of the new nonlinear material, Ca(4)GdO(BO(3))(3) (GdCOB), is reported. This crystal belongs to the calcium oxoborate family. It has attractive nonlinear properties that can be of great interest in integrated optics applications. We used a method of He(+) implantation to fabricate waveguides in GdCOB crystals by creating a buried layer of lowered refractive index a few micrometers beneath the surface. Both TE and TM modes were observed. Therefore, according to the Y cut of the crystal, refractive-index values of n(x) , n(y) , and n(z) were obtained. Index profiles were reconstructed by an improved inverse WKB method. The profiles showed a steplike index behavior, indicating that the guiding region obtained was of good optical quality.

[Burkitt's disease in the Ivory Coast in 1988]. / La maladie de Burkitt en Côte-d'Ivoire en 1988.

Burkitt's lymphoma, or endemic hematosarcoma, is the major cancer in childhood and the 6th most common cancer in the Ivory Coast. The authors review classical ideas regarding the disease and stress some recent findings.