A novel, all-fiber-integrated supercontinuum (SC) laser is demonstrated and provides up to 10.5 W time-averaged power with a continuous spectrum from ~0.8 to 4 mum. The SC is generated in a combination of standard single-mode fibers and ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fluoride fibers pumped by a laser-diode-based cladding-pumped fiber amplifier system. The output SC pulse pattern can be modulated by directly modulating the seed laser diode. Near-diffraction-limited beam qualities are maintained over the entire SC spectrum. The SC average power is also linearly scalable by varying the input pump power and pulse repetition rate. We further investigate the theoretical limitations on the achievable average power handling and spectral width for the SC generation in ZBLAN fibers. Based on the thermal modeling, the standard ZBLAN fiber can handle a time-averaged power up to ~15 W, which can be further scaled up to ~40 W with a proper thermal coating applied onto the ZBLAN fiber. The SC long-wavelength edge is limited by the nonlinear wavelength generation processes, fiber bend-induced loss, and glass material loss. By using a ZBLAN fiber with a 0.3 numerical aperture, the SC spectrum could extend out to ~4.5 mum, which is then limited by the material loss.

10.5 W Time-Averaged Power Mid-IR Supercontinuum Generation Extending Beyond 4 $\mu$ m With Direct Pulse Pattern Modulation

The invention relates to a method for forming a three-dimensional article through successive fusion of locations of a powder bed. The method comprising: providing a model of said three-dimensional article; applying a powder layer on a work table; determining a maximum scan length of an energy beam; directing said energy beam from a first energy beam source over said work table with constant energy causing said first powder layer to fuse in first selected locations according to said model to form a first cross section of said three-dimensional article, wherein locations with a shorter scan length than said maximum scan length is provided with a time sink before and/or after said scan line so that the time period between each two adjacent scan lines is constant throughout the manufacture of said three-dimensional article.

Method for additive manufacturing

Microstructured optical fibers (MOFs) are traditionally prepared using the stack and draw technique. In order to avoid the interfaces problems observed in chalcogenide glasses, we have developed a new casting method to prepare the chalcogenide preform. This method allows to reach optical losses around 0.4 dB/m at 1.55 µm and less than 0.05 dB/m in the mid IR. Various As(38)Se(62) chalcogenide microstructured fibers have been prepared in order to combine large non linear index of these glasses with the mode control offered by MOF structures. Small core fibers have been drawn to enhance the non linearities. In one of these, three Stokes order have been generated by Raman scattering in a suspended core MOF pumped at 1995 nm.

/pdf/low-loss-microstructured-chalcogenide-fibers-for-large-non-26s95pdfi6.pdf

Low loss microstructured chalcogenide fibers for large non linear effects at 1995 nm.

High-power mid-infrared supercontinuum sources: Current status and future perspectives

Various embodiments provide a method and apparatus for forming a three-dimensional article through successive fusion of parts of at least one layer of a powder bed provided on a work table in an additive manufacturing machine, which parts corresponds to successive cross sections of the three-dimensional article. The method comprises the steps of: applying a layer of predetermined thickness of powder particles on the work table, applying a coating on at least a portion of the powder particles, which coating is at least partially covering the powder particles, and fusing the powder particles on the work table with an electron beam.

Method and apparatus for additive manufacturing

Cascaded Raman wavelength shifting up to three orders from 1553 nm to 1867 nm is demonstrated in As2S3-chalcogenide fibers. Due to a long zero dispersion wavelength for the sulfide fiber (>4.5 μm), pumping the fiber at 1553 nm results in generation of cascaded Stokes orders based on stimulated Raman scattering. Using the threshold power for the Raman orders, we estimate the Raman gain coefficient for the As2S3 fibers to be ~5.7×10-12 m/W at 1550 nm. Observation of higher Raman orders is limited by damage to the fiber at input intensities >1 GW/cm2.

http://omnisciinc.com/files/2_20060831-Kulkarni-OpticsExp.PDF

Third order cascaded Raman wavelength shifting in chalcogenide fibers and determination of Raman gain coefficient

The invention is directed to chalcogenide glasses suitable for use in plastics forming processes. The glasses have the general formula YZ, where Y is Ge, As, Sb or a mixture of two or more of the same; Z is S, Se, Te, or a mixture of two or more of the same; and Y and Z are present in amounts (in atomic/element percent) in the range of Y=15–70% and Z=30–85%. The chalcogenide glasses of the invention have a 10,000 poise temperature of 400° C. and are resistant to crystallization when processed at high shear rates at their 10,000 poise temperature. The glasses can be used to make, among other items, molded telecommunication elements, lenses and infrared sensing devices.

Chalcogenide glass for low viscosity extrusion and injection molding

A die for forming an extrusion includes a die body, a body feed section and an extrusion forming section. The die body may include an inlet and an outlet defining an extrudate flow path through the die body. The body feed section may be positioned between the inlet and outlet and includes an arrangement of body feed channels. The extrusion forming section may be positioned between the body feed section and the outlet and includes a thin-wall forming portion fluidly coupled to at least one thick-wall forming portion. The thin-wall forming portion may include an array of pins extending from the body feed section towards the outlet and the thick-wall forming portion may include at least one baffle section positioned in the extrudate flow path through the thick-wall forming portion. The area of the thick-wall forming portion may be greater than an interstitial area between the pins.

Dies For Forming Extrusions With Thick and Thin Walls

High purity direct deposit vitrified silicon oxyfluoride glass suitable for use as a photomask substrates for photolithography applications in the VUV wavelength region below 190 nm is disclosed. The inventive direct deposit vitrified silicon oxyfluoride glass is transmissive at wavelengths around 157 nm, making it particularly useful as a photomask substrate at the 157 nm wavelength region. The inventive photomask substrate is a dry direct deposit vitrified silicon oxyfluoride glass which exhibits very high transmittance in the vacuum ultraviolet (VUV) wavelength region while maintaining the excellent thermal and physical properties generally associated with high purity fused silica. In addition to containing fluorine and having little or no OH content, the inventive direct deposit vitrified silicon oxyfluoride glass suitable for use as a photomask substrate at 157 nm is also characterized by having less than 1×1017 molecules/cm3 of molecular hydrogen and low chlorine levels.

Vacuum ultraviolet transmitting direct deposit vitrified silicon oxyfluoride lithography glass photomask blanks

The present invention is directed to a method of making an ultra dry high purity, Cl-free, F doped fused silica glass. Silica powder or soot preforms are used to form a glass under conditions to provide a desired level of F doping while reducing the Cl and −OH concentrations to trace levels. The method includes providing a glass precursor in the from of a silica powder or soot preform. The powder is heated in a furnace. The powder is exposed to a F-species at a predetermined temperature and time sufficient to melt the powder and form a high purity fused silica glass in the bottom of said furnace.

Stephen Charles Currie

Papers

Third order cascaded Raman wavelength shifting in chalcogenide fibers and determination of Raman gain coefficient

Chalcogenide glass for low viscosity extrusion and injection molding

Dies For Forming Extrusions With Thick and Thin Walls

Vacuum ultraviolet transmitting direct deposit vitrified silicon oxyfluoride lithography glass photomask blanks

Method of making ultra-dry, Cl-free and F-doped high purity fused silica