LPP EUV light source employing high power CO2 laser

We are developing a high power CO2 laser system for a LPP EUV light source. Recent theoretical and experimental data demonstrate the advantages of the combination of a CO2 laser with a Sn target including the generation of a high CE and low debris plasma with low energy ions and low out-of-band radiation. Our laser system is a short pulse CO2 MOPA (Master Oscillator Power Amplifier) system with 22 ns pulse width and multi kW average power at 100 kHz repetition rate. We achieved an average laser power of 8 kW with a single laser beam having very good beam quality. A EUV in-band power of 60 W at the intermediate focus was generated irradiating a rotating tin plate with 6 kW laser power.