Frequency‐doubled short nanosecond fiber lasers for glass drilling and grinding

We developed a fiber laser based 515 nm single-mode green laser with pulse width of 5 ns, peak power of greater than 20 kW, and repetition rates from 100 kHz to 500 kHz, which is suitable for glass drilling and grinding. The lithium triborate (LBO) crystal is used for second harmonic generation of 515 nm laser with efficiency of 68%. Glass drilling speed of 50 mm/s @ 0.5 mm thick glass was achieved for industrial environment continuous operation, which is equivalent to 1 s of time to drill a 4 mm diameter hole on a 2 mm thick glass. The typical chip sizes for the rear and front sides are 80 mu m and 120 mu m, respectively. Seven thousand holes are drilled in 24 hours in glass product line, and the success rate is larger than 99.7%. This laser glass drilling approach is rapidly accepted by glass industrial. Glass surface grinding was demonstrated by using 1 ns pulse width 515 nm lasers.