Heinz P. Weber

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Planar optical waveguides consisting of thin dielectric films with metal cladding have been investigated theoretically and experimentally. A computer program was devised to provide the phase and attenuation constants and wavefunctions for TE and TM modes in symmetric and asymmetric guides. Approximate expressions suitable for slide-rule calculation were(More)
We report on an upconversion cascade laser in an erbium-doped ZBLAN fiber emitting simultaneously on the three transitions (4)S(3/2) ? (4)I(9/2) at 1.7 microm , (4)I(11/2) ? (4)I(13/2) at 2.7 microm , and (4)I(13/2) ? (4)I(15/2) at 1.6 microm . At moderate pump powers, the laser transition at 1.6 microm supports 2.7-microm lasing and permits a slope(More)
In computer simulations the mechanisms that lead to room-temperature continuous-wave green upconversion lasing in Er’ ’ :LiYli; are investigated. The rate-equation system considers the full erbium level scheme up to ‘H 9,3, ground-state depletion. excited-state absorption on the pump and laser wavelengths, three interionic processes, stimulat.ed emission,(More)
We report on the results of proton and gamma irradiation tests performed on nonlinear crystals for second- (SHG) and third-harmonic generation. Beta-barium borate (BBO), lithium triborate (LBO), and KTP crystals were exposed to three different energies of proton radiation (8, 70, and 300 MeV) and incremental doses of gamma radiation (up to 139 krad) in(More)
In medical imaging different techniques have been developed to gain information from inside a tissue. Optoacoustics is a method to generate tomography pictures of tissue using Q-switched laser pulses. Due to thermal and pressure confinement, a short light pulse generates a pressure distribution inside tissue, which mirrors absorbing structures and can be(More)
Among different types of lasers, the erbium laser exhibits particularly favourable characteristics for ear surgery. Experiments with application of erbium laser pulses to the isolated stapes connected to an inner ear model confirmed that there was virtually no thermal effect to the inner ear liquid and that the border damage zone on the stapes footplate(More)
BACKGROUND AND OBJECTIVES Laser-assisted stapedotomy has become a well-established alternative to the mechanical drilling method. The goal of this study is to quantify the mechanical and thermal tissue effects and to determine optimum erbium laser parameters for safe clinical treatment. STUDY DESIGN/MATERIALS AND METHODS On an inner ear model,(More)