Моделирование уравнений проекционного осциллографирования на машине "ЭМУ-10"

The passive-alignment-packaging technique presented in this work provides a method for mounting tolerance-insensitive optical components e.g. non-linear crystals by means of mechanical stops. The requested tolerances for the angle deviation are ±100 µrad and for the position tolerance ±100 µm. Only the angle tolerances were investigated, because they are more critical. The measurements were carried out with an autocollimator. Fused silica components were used for test series. A solder investigation was carried out. Different types of solder were tested. Due to good solderability on air and low induced stress in optical components, Sn based solders were indicated as the most suitable solders. In addition several concepts of reflow soldering configuration were realized. In the first iteration a system with only the alignment of the yaw angle was implemented. The deviation for all materials after the thermal and mechanical cycling was within the tolerances. The solderability of BBO and LBO crystals was investigated and concepts for mounting were developed

Laparoskopische Cholezystektomie bei Pfortaderthrombose mit kavernöser Transformation

We present the world's first laser at 515 nm with sub-picosecond pulses and an average power of 445 W. To realize this beam source we utilize an Yb:YAG-based infrared laser consisting of a fiber MOPA system as a seed source, a rod-type pre-amplifier and two Innoslab power amplifier stages. The infrared system delivers up to 930 W of average power at repetition rates between 10 and 50 MHz and with pulse durations around 800 fs. The beam quality in the infrared is M-2 = 1.1 and 1.5 in fast and slow axis. As a frequency doubler we chose a Type-I critically phase-matched Lithium Triborate (LBO) crystal in a single-pass configuration. To preserve the infrared beam quality and pulse duration, the conversion was carefully modeled using numerical calculations. These take dispersion-related and thermal effects into account, thus enabling us to provide precise predictions of the properties of the frequency-doubled beam. To be able to model the influence of thermal dephasing correctly and to choose appropriate crystals accordingly, we performed extensive absorption measurements of all crystals used for conversion experiments. These measurements provide the input data for the thermal FEM analysis and calculation. We used a Photothermal Commonpath Interferometer (PCI) to obtain space-resolved absorption data in the bulk and at the surfaces of the LBO crystals. The absorption was measured at 1030 nm as well as at 515 nm in order to take into account the different absorption behavior at both occurring wavelengths

Radiation tests on erbium-doped garnet crystals for spaceborne CH4-Lidar applications

A test campaign for assessing the radiation hardness of different Erbium-doped garnet crystals including Er:YAG and a compositionally tuned Er:YAG/Er:LuAG mixed garnet is reported. Tests with proton and gamma radiation have been performed with parameters mimicking a 3-year low-earth-orbit satellite mission like MERLIN or ADM-Aeolus. For each test sample broadband transmission spectra in the wavelength range of 500 nm -1700 nm and characteristic laser curves from a test laser oscillator have been measured. Radiation-induced losses have been calculated from the obtained data. The results indicate that gamma radiation is the dominant loss source with about 0.5 %/cm radiation-induced losses for the nominal dose of the chosen mission scenario