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  • 1990-1994  (10)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 3440-3446 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ion implantation into Nd:YAG has been used to produce waveguides which are capable of supporting laser action. The refractive index profiles have been characterized as a function of ion dose and energy, implant temperature, and subsequent thermal annealing. Transmission losses down to 1.2 dB/cm have been obtained in the optimized waveguides. There is a temperature independent index enhancement of ∼0.15% in the electronic stopping (guiding) region. The nuclear collision damage is temperature dependent, and shows an initial index increase (∼0.3% for dose 1 × 1016 ions/cm2), but a subsequent decrease of up to several percent, which forms an optical barrier, as has been observed in many other crystalline materials. The best mode confinement and attenuation is obtained by utilizing the low dose nuclear index enhancement produced by several equally spaced implants (multiple energy) to give a broad well with Δn∼0.25%. Several unusual features of the profiles are reported and discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1185-1189 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An extra "strange'' mode has been observed in the extraordinary index mode spectrum of certain optical waveguides produced by He+ ion implantation in LiNbO3. This behaves differently to the normal modes contained within the main optical well of the waveguide, for example when observed at varying wavelengths or after surface polishing. The mode has been shown to be a real guided-wave mode, and has been attributed to a subsidiary optical well located beyond the main nuclear damage optical barrier. It is suggested that this well is produced by the radiation-enhanced diffusion of Li+ towards the nuclear damage barrier, and the mechanism is compared with that responsible for the well on the near side of the barrier which causes the previously reported "missing'' modes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 2695-2699 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Second-harmonic generation (SHG) has been successfully performed in ion-implanted planar waveguides in KTiOPO4. The waveguides were formed by helium implantation, and SHG was achieved using type 2 zero order mode phase matching at a wavelength of ∼1.07 μm. The results indicate that the high nonlinearity of the material remains in the guiding region after ion implantation. The conversion efficiency in a typical guide is estimated at ∼25% for ∼1 μJ pulsed excitation. At a lower input power level, the harmonic green output from the waveguide is 20 times higher than that from the bulk for the same amount of fundamental power. This clearly demonstrates the advantage of using waveguides in achieving frequency doubling for integrated optical devices.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 49-52 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Optical waveguides have been formed by helium-ion implantation in KTaO3. The implantation forms a confinement barrier near the projected range of the ion by decreasing the refractive index as much as 16% for ion doses of 4×1016 ions/cm2. This is the highest refractive-index change yet reported for ion-implanted crystalline planar waveguides. Guiding modes (with moderately low loss) are produced without the need for annealing out of color centers. During annealing studies, the index change reduces during an anneal stage near 400 °C, but waveguiding is maintained even after anneals to 900 °C. Loss measurements indicate a planar-waveguide loss of 〈1 dB/cm after a 400 °C anneal.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 1871-1873 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Sapphire samples (Al2O3) were implanted with 400-keV ions at a dose of 1×1016 ions cm−2. A comparison was made between furnace annealing and pulsed laser annealing of the implanted samples. Furnace annealing to 1200 °C, followed by excimer laser anneals, resulted in an increase of the cathodoluminescence emission intensity of the implanted europium by a factor of ∼20. This enhanced intensity is ∼50 times that of the signal prior to any form annealing treatment. It is proposed that the laser anneals dissociate Eu related clusters. The Eu 622-nm lifetime reached 1.53 ms compared with an original postimplant value of 0.14 ms. © 1994 American Institue of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 384-386 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the first example of second-harmonic generation in a quartz ion-implanted waveguide. The example operated with low-power pumping near 783 nm. The harmonic production near 392 nm follows a square law dependence. A detailed fit of the pumping efficiency with wavelength suggests there is a phase match throughout the length (z propagating) of the sample. The mode match used was between TE0 of the fundamental and TE2 of the harmonic (ordinary index).
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 2637-2639 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Planar waveguides have been fabricated in single-crystal Nd-doped yttrium oxy-orthosilicate (Nd:Y2SiO5) using 2.0 MeV He+ ion implantation at doses of around 1016 ions/cm2. Refractive index profiles of the waveguides are presented. The losses were found to be lower for TE polarized modes with the minimum loss achieved to date being 0.71 dB/cm after annealing. Photoluminescence studies indicate that both the spectral line shape and the radiative lifetimes of the waveguides fully recover to bulk values after annealing.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 5754-5756 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Silver colloids have been formed by ion implantation in float glass. Subsequent annealing methods alter the size distribution and optical reflectivity of the colloids. Furnace anneals and rapid flame heating convert large colloids into smaller units but excimer laser annealing appears to cause a dissolution of silver into the glass network.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Physics and chemistry of minerals 20 (1993), S. 353-361 
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Variations in thermoluminescence spectra are reported for four types of geological quartz examined with a new spectrometer featuring dual imaging photon detectors that separately and simultaneously detect (1) uv-blue (200–450 nm) and (2) blue to near infrared (400–800 nm) emission. Samples show striking differences which appear to be characteristic of their geological origin. Volcanic quartz phenocrysts from acid volcanics show red thermoluminescence (TL) emission bands centered at 620–630 nm that are 100 times more intense than similar bands in other quartz, while a violet emission at 420–435 nm was observed exclusively in igneous quartz (volcanic and granitic). A broad emission band centered at 560–580 nm was observed only in quartz formed hydrothermally. Massive quartz from Li-rich pegmatite bodies shows narrow, intense 470 nm emission bands at 230° C apparently related to Al and to Ge defects detected with electron paramagnetic resonance (EPR), and emission bands at 330 and 280 nm, possibly related to recombination at oxygen vacancies. The common 380 nm emission band of quartz was observed in both volcanic and granitic quartz, but was not detected in either the pegmatitic or the hydrothermal vein quartz. Observed spectral variation is identified as a potential source of error in luminescence dating.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 37 (1991), S. 1153-1160 
    ISSN: 1572-8943
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Das Radiolumineszenzspektrum von mit Nd versetzten Ge-Siliziumoxidfasern ändert sich durch den Einfluß von vorheriger Bestrahlung und thermischem Tempern. Ursprünglich besteht das Spektrum aus einer Gaußschen Bande mit dem Mittelpunkt bei etwa 3.1 eV (400 nm). Nach Bestrahlung und Erhitzen zeigt sich in der Nähe von 2.4 eV (520 nm) eine zusätzliche, asymmetrische Bande. An der Spitze dieser Bande befindet sich ein Linienspektrum, was internen Übergängen von Nd3+ zugeschrieben werden kann. Auf der Grundlage der spektroskopischen Angaben und vorangehender Resultate aus Thermolumineszenzuntersuchungen wurde für die Lumineszenz und den Einfluß des thermischen Temperas ein Modell entwickelt. Blaue bzw. grüne Banden werden O2 − Molekülionen bzw. Leerstellenzentren in der Nähe von Nd3+-Ionen zugeschrieben.
    Notes: Abstract The radioluminescence spectrum of Ge-silica fibres doped with Nd is found to change by the effect of pre-irradiation and thermal annealing. Originally the spectrum consists of a gaussian band centred near 3.1 eV (400 nm). Following the irradiation and heating an additional asymmetric band appears near 2.4 eV (520 nm). On top of this band there is a line spectrum, which can be ascribed to internal transitions of the Nd3+. On the basis of the spectroscopic data and previous results of thermoluminescence measurements, a model is suggested for the luminescence and the effect of the thermal annealing. The blue and green bands are ascribed to an O2 − molecular ion and a hole centre near the Nd3+ ion, respectively.
    Type of Medium: Electronic Resource
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