Cutting speed and behaviors of ice using Yb-doped fiber laser

The use of a laser to cut or drill ice has been proposed and demonstrated multiple times in previous decades as a novel, but never adopted, machining tool in glaciology and paleoclimate studies. However, with the rapid development of high power fiber-laser technology over the past few decades, it is timely to perform further studies using this new tool. An investigation is made herein on the cutting of ice using a Yb-doped fiber laser emitting at a wavelength of 1070 nm, the most extensively developed and highest power fiber laser technology, in pulsed and continuous-wave operation. Visible-light observations of clear tap water ice samples, moving at a constant velocity relative to a pulsed laser beam, demonstrate a linear relationship between the duration of a millisecond-range laser pulse and the depth of the meltwater-free cut formed in response. Thermal imaging of the irradiated face shows that peripheral heating trends linearly for pulse lengths greater than 5 ms. A comparison of pulse trains with a constant time-averaged power suggests that shorter pulses are advantageous in slot-cutting efficiency and in minimizing visible alterations in the surrounding ice. These results demonstrate the viability of powerful fiber-compatible lasers as a tool for ice sample retrieval and processing.