We demonstrate chalcogenide optical fiber couplers with a power-dependent coupling coefficient. The couplers are designed and fabricated using an As2Se3 fiber and characterized at a wavelength of 1938 nm, leading to a critical power of 126 W, the lowest ever reported for any optical fiber coupler. These nonlinear couplers enable all-optical switching and will be useful for passive mode-locking over a wide wavelength range from the telecommunication band to the mid-infrared.
Eccrine spiradenoma is a benign and rare adnexal tumor originating from cutaneous eccrine sweat glands. It usually presents as a solitary lesion. It can have different presentations, including a blaschkoid arrangement which is rare. Malignant transformation is possible and usually occurs after a long period of latency in multifocal types.
We report the case of bronchial carcinoma revealed by metastatic skin nodules on the scalp. This fairly common mode of discovery is often associated with poor prognosis. This study aims to underline the importance of directing the search for a primary lung cancer in cases of secondary skin involvement.
Adenocarcinoma/diagnosis , Scalp/pathology , Skin Neoplasms/secondary , Adenocarcinoma/pathology , Bronchial Neoplasms/diagnosis , Bronchial Neoplasms/pathology , Humans , Male , Middle Aged , Prognosis , Skin Neoplasms/pathology
We report the first chalcogenide microwire designed with all-normal dispersion to generate supercontinuum by optical wave breaking, a low-noise nonlinear process. The chalcogenide (As2S3) microwire is coated with PMMA and tapered to a diameter of 0.58 µm to achieve the all-normal dispersion regime. The generated supercontinuum spectrum spans over an octave from 960 to >2500 nm using a microwire length of only 3 mm and a low pulse energy of 150 pJ.
We report the first mode-locked fiber laser using a chalcogenide microwire as the nonlinear medium. The laser is passively mode-locked with nonlinear polarization rotation and can be adjusted for the emission of solitons or noise-like pulses. The use of the microwire leads to a mode-locking threshold at the microwatt level and shortens the cavity length by 4 orders of magnitude with respect to other lasers of its kind. The controlled birefringence of the microwire, combined with a linear polarizer in the cavity, enables multiwavelength laser operation with tunable central wavelength, switchable wavelength separation, and a variable number of laser wavelengths.
Marine sponges are a potential source of new molecules with diverse biological activities. We have previously isolated a sphingosine derivative, (9Z)-2-amino-docos-9-ene-1,3,13,14-tetraol (Haliscosamine) from the Moroccan sea sponge Haliclona viscosa. The aim of this study was to test Haliscosamine in vitro and in vivo for its antifungal activity against Fusarium oxysporum f.sp. melonis causing fusarium wilt of melon. Overall, in vitro test showed that haliscosamine has a similar effect as DESOGERME SP VEGETAUX®. In addition, in vivo showed a significant effect against Fusarium oxysporum f.sp. melonis. Taking to gather, our results suggest that haliscosamine constitutes a potential candidate against Fusarium oxysporum f.sp. melonis and the possibility to use in phytopathology.
Laser emission is demonstrated at a wavelength of 3.766 µm in a cascaded Raman gain device. The laser cavity is made of two nested pairs of fiber Bragg gratings inscribed in a 2.8 m length of low-loss As2S3 fiber. An erbium-doped fluoride glass quasi-CW fiber laser emitting at 3.005 µm is used to pump the cascaded Raman cavity, which converts the pump wavelength successively to the first and second Stokes orders, respectively at 3.340 and 3.766 µm. A laser output peak power in excess of 100 mW is obtained with a lasing efficiency of about 8.3% with respect to the launched pump power. This represents the highest emission wavelength delivered by a fiber laser operating at room temperature.
We demonstrate the supercontinuum (SC) generation in a suspended-core As(2)S(3) chalcogenide microstructured optical fiber (MOF). The variation of SC is investigated by changing the fiber length, pump peak power and pump wavelength. In the case of long fibers (20 and 40 cm), the SC ranges are discontinuous and stop at the wavelengths shorter than 3500 nm, due to the absorption of fiber. In the case of short fibers (1.3 and 2.4 cm), the SC ranges are continuous and can extend to the wavelengths longer than 4 µm. The SC broadening is observed when the pump peak power increases from 0.24 to 1.32 kW at 2500 nm. The SC range increases with the pump wavelength changing from 2200 to 2600 nm, corresponding to the dispersion of As(2)S(3) MOF from the normal to anomalous region. The SC generation is simulated by the generalized nonlinear Schrödinger equation. The simulation includes the SC difference between 1.3 and 2.4 cm long fiber by 2500 nm pumping, the variation of SC with pump peak power in 2.4 cm long fiber, and the variation of SC with pump wavelength in 1.3 cm long fiber. The simulation agrees well with the experiment.
Arsenicals/chemistry , Chalcogens/chemistry , Fiber Optic Technology/instrumentation , Lasers , Lighting/instrumentation , Sulfides/chemistry , Equipment Design , Equipment Failure Analysis , Infrared Rays , Materials Testing , Miniaturization
We report the generation of a broadband supercontinuum (SC) spanning from 1260 to 2200 nm using a 10 cm long As2Se3 chalcogenide (ChG) wire pumped at a wavelength of 1550 nm. Such a wide SC in As2Se3 is obtained by avoiding the effects of two-photon absorption normally observed at a wavelength of 1550 nm. For this purpose, the pump soliton is initially self-frequency shifted toward longer wavelength by means of the Raman effect in standard silica fiber before being launched into the ChG wire for spectral broadening.
We propose a new way to realize a microfiber optical resonator by implementing the topology of a reef knot using two microfibers. We describe how this structure, which includes 4 ports and can serve as an add-drop filter, can be fabricated. Resonances in an all-silica reef knot are measured and good fits are obtained from a simple resonator model. We also show the feasibility of assembling a hybrid silica-chalcogenide reef knot structure.
Chalcogens/chemistry , Fiber Optic Technology/instrumentation , Optical Tweezers , Oscillometry/instrumentation , Silicon Dioxide/chemistry , Transducers , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Feasibility Studies , Miniaturization , Reproducibility of Results , Sensitivity and Specificity
