This Small Business Innovation Research (SBIR) Phase I project proposes to develop innovative blue and green lasers based on multi-pass second harmonic generation (SHG). It utilizes a simple Galilean telescope to solve many of the problems associated with this promising technical approach. The goal of the Phase I feasibility study is to develop a multi-pass SHG laser with 20 milliwatts of output power and excellent beam quality. The proposed lasers are expected to be 2 to 5 times more reliable than argon ion and frequency-doubled Nd:YAG lasers (20,000 hours mean time to first failure vs. 4,000 to 10,000 hours). In quantity, the parts for the proposed lasers would cost about $625 (vs. several thousand dollars for a frequency-doubled YAG laser).<br/><br/>The commercial applications of this project are in bio-instrumentation (light-induced fluorescence microscopy, flow cytometry, capillary electrophoresis, DNA sequencing, and confocal microscopy), semiconductor inspection (photomask inspection, wafer alignment, confocal microscopy, and wafer process monitoring), and reprographics (high-speed laser printers, video CD storage, and medical imaging and diagnostics).