1. ©LZH M.Frede Aug.02 G020326-00-Z Status of Laser Zentrum Hannover Laser Program Maik Frede Martina Brendel, Carsten Fallnich, Renê Gau, Philipp Huke, Ralf Wilhelm, Ivo Zawischa Laser Zentrum Hannover Aug. 2002 LSC Meeting-Hanford LIGO-G020326-00-Z

2. ©LZH M.Frede Aug.02 G020326-00-Z Medium Power Stage fundamental mode output : 12 W  opt = 42%, M 2 < 1.2

3. ©LZH M.Frede Aug.02 G020326-00-Z Medium Power Stage doubling output power by extension from V - to ring resonator symmetric axis

4. ©LZH M.Frede Aug.02 G020326-00-Z High Power Stage - Setup

5. ©LZH M.Frede Aug.02 G020326-00-Z High Power Stage - Setup

6. ©LZH M.Frede Aug.02 G020326-00-Z Modeling of the realized laser system

7. ©LZH M.Frede Aug.02 G020326-00-Z High Power Stage - first Results multimode Resonator ( M 2 < 7, OC = 12% )

8. ©LZH M.Frede Aug.02 G020326-00-Z High Power Stage - first Results fundamental mode resonator ( M 2 < 1.3 )

9. ©LZH M.Frede Aug.02 G020326-00-Z High Power Stage - Results fundamental mode output power : 97 W M 2 x,y :1.25 optical efficiency : 25% polarization ratio : > 200 depolarization loss < 0,5% M 2 measurements with Beam Map, Data Ray Inc. output power and M 2 are limited by aberrations !

10. ©LZH M.Frede Aug.02 G020326-00-Z Homogenized vs Non-Homogenized Pumping Scheme Increase of spherical aberrations through asymmetrical pump light distribution non - homogenized pump light distribution

11. ©LZH M.Frede Aug.02 G020326-00-Z Pump light homogenization fiber arrangementfluorescence w/o homogenization fluorescence with homogenization

12. ©LZH M.Frede Aug.02 G020326-00-Z Fluorescence under assuming diode failure fiber arrangementfluorescence non-significant change in fluorescence distribution stable laser conditions by holding pump power constant maintenance during laser operation possible

13. ©LZH M.Frede Aug.02 G020326-00-Z Preparation of Wave front measurement measure wave front distortion from optical components measure thermal lens and aberrations data acquisition for theoretical model optimize crystal cooling

14. ©LZH M.Frede Aug.02 G020326-00-Z Outlook / Summary laser modeling high power stage P = 97 W M 2 = 1.25 wave front measurements and pump light homogenization single frequency P > 100 W M 2 < 1.1 200W Advanced LIGO Laser