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Q: Quantenoptik
Q 0: Postdeadline: Talks
Q 0.6: Vortrag
Dienstag, 3. April 2001, 20:20–20:30, H 104
Diode-pumped high-repetition rate erbium laser for medical applications — •Holger Ernst1, Carsten Ziolek1, Holger Lubatschowski1, and Wolfgang Ertmer2 — 1Laser Zentrum Hannover e.V., Hollerithallee 8, 30419 Hannover — 2Institut für Quantenoptik, Universität Hannover, Welfengarten 1, 30169 Hannover
Erbium lasers are known as very precise instruments in medical surgery due to the high water absorption in the 3 µm wavelength range. Especially in cataract surgery erbium lasers are promising devices. Nevertheless to be competitive to the common ultrasound method repetition rates > 200 Hz at output energies of 5 to 10 mJ are necessary. These parameters were not achieved by erbium lasers until now. To reach this goal, we developed a new dioded-pumped laser, based on a transversal pumped slab concept. A hexagonal shaped 50 at.% Er:YAG crystal, containing 5 total internal reflection (TIR) - surfaces, is pumped by 3 qcw stacked array diode lasers. These diode lasers are emitting at a wavelength about 962 nm with 5 nm FWHM and 220 W peak power each. They are focused to the TIR-surfaces with a delivering efficiency of 75 %. The choosen setup has a 1.8 mm crystal penetration depth (1/e2) of the pump light and therefore a geometric overlap of 75 ± 5 % between the pump and laser mode. The total system including two plane external mirrors to form the folded TIR-cavity has a dimension of 150 × 200 mm only. In our experiments we demonstrated 2.5 W output power at a repetition rate of 300 Hz and 1.2 W at 600 Hz. Moreover, differential efficiencies up to 18.3 % at an optimum pump pulse width in the range of 300 µs were achieved.