Abstract: Maximizing the glass forming ability of low metal-phosphate content fluoride-based glasses allows the fabrication of large-size “crystal-free” HEL windows. This involves the addition of glass stabilizer oxides such as SiO2, TiO2, Al2O3. In situ quenching is used to fabricate large-scale HEL windows substantially free of crystals, bubbles and striation.

Abstract: A handheld device for infrared reflectance measurements of samples for identification of the sample materials is a self-contained portable unit built into a handheld housing. The housing includes a window and optics on a bench adjacent the window, so that the optics will be aligned with the sample when the device is placed directly against the sample. The optics include a broad-band IR light source (ordinary lamp) shining onto an acousto-optic tunable filter (AOTF), which passes narrow-band IR light with a swept frequency; a lens focussing the IR through the window onto the sample; and a reflectance detector aligned with the window of the housing to pick up reflected light. A computer, which may be mounted in the housing, compares the detected reflectance spectrum with stored sample data spectra, and identifies the material or the components of the material and their proportions.

Abstract: A biocompatible optical fiber tip derived from fluorophosphate glasses whose composition includes P--O compounds, AlF.sub.3, alkali-earth fluorides, and/or alkali fluorides, and lanthanides fluoride is used with a medical laser to transmit power for surgical applications.

Abstract: An improved optical glass fiber for transmitting mid infrared wavelength laser light in surgical instruments, includes a heavy-metal oxide component, preferably GeO.sub.2 doped with heavier cations and anions, and which is capable of delivering at least three watts of laser power continuously for more than ten minutes, without failure. This glass fiber has an .alpha.(dB/m) at 2.94 .mu.m of 10, preferably less, and can transmit at least 27% of the IR through a thickness of one foot.

Abstract: An improved optical fiber for transmitting mid-infrared wavelength laser light in surgical instruments, includes, a heavy-metal oxide component, preferably GeO.sub.2 doped with heavier cations and anions, is capable of delivering of at least three watts of laser power continuously for more than ten minutes, without failure. This glass fiber has an .alpha.(dB/m) at 2.94.mu.m of 10, preferably less, and can transmit at least 27% of the IR through a thickness of one foot.

Abstract: An acousto-optical filter (AOTF) is used in a spectrometer for analysis of samples. The spectrometer provides continuous wave RF excitation through the crystal, and the spectrometer provides control and modulation for said RF source. The signal to noise ratio is improved by use of a lock-in amplifier which demodulates the modulation frequency. Fiber optics are used to connect the crystal to the source, and the source to the detection system. A digital lock-in amplifier is designed which increases the efficiency, accuracy, sensitivity and decreases the cost of conventional analog lock-in amplifier.

Abstract: Improved fluoride glass optical fibers are produced by a process introducing several improvements in the production of fluoride glass preforms and the drawing of fibers therefrom. Reduced bubble formation and crystallization are obtained by vertically spinning a fluoride glass melt within a glass cladding tube at a high rotational speed, or alternatively, pouring a flouride glass core melt into a cladding tube while slowly raising the mold from an inclined position to a vertical position, or alternatively, introducing a core tube inside a cladding tube. The production of fibers is enhanced if at least one production phase, i.e., preform formation or fiber drawing, is conducted in an atmosphere containing reactive gases that scavenge molecules that could otherwise react with, hydrolyze and oxidize the fluoride glass. The disclosure also describes several devices uniquely useful in the process of the present invention.

Abstract: A process for producing high quality optical glass from fluoride glasses comprising preparing a melt of the glass and then cooling the melt in-situ inside the melt crucible. The in-situ quenching technique can be improved by narrowing the temperature range between the liquidus temperature and the glass transition temperature of the glass. The stability of the fluoride glass can be increased and the liquidus temperature of the glass can be lowered by doping the glass with a chloride dopant. Thorium tetrafluoride can be added to the chloride-doped glass in order to increase the chemical stability of the glass.