Recently, polycrystalline silicon thin film solar cells on glass are fabricated by a laser induced liquid phase crystallization (LPC) process. This study compares a new economic diode laser emitting a line focus at 980 nm with the 808 nm laser normally used concerning its absorption during LPC. We measured the optical constants of amorphous silicon by spectral ellipsometry and UV/VIS spectroscopy. Together with literature data for crystalline and liquid silicon combined with numerical temperature simulations we calculated the absorption during LPC and the overall power needed for successful crystallization. Solar cells prepared with both laser types show comparable crystallographic and optoelectronic characteristics. Concerning the overwhelming economic advantages the use of such a 980 nm diode laser system will lead to a considerable cost reduction in the potential industrial production.