Femtosecond ablation using an intensity spatial light modulator: what is the minimum machinable feature size?

Mills, B., Heath, D.J., Grant-Jacob, J.A., Feinäugle, M. and Eason, R.W. (2014) Femtosecond ablation using an intensity spatial light modulator: what is the minimum machinable feature size? Materials Research Society Spring Meeting E-MRS '14, , Lille, France. 26 - 30 May 2014.

Abstract

Advances in digital multimirror devices (DMDs), which consist of arrays of micron-sized mirrors that are individually switchable, have recently led to their use in a variety of applications in optics and laser science. Here, a DMD is used as an intensity spatial light modulator for 800nm, 1mJ, 150fs pulses, at a 1kHz repetition rate, for high-resolution subtractive machining of thin films. The use of a high-energy laser pulse enables an entire complex pattern, with approximately 1000 by 1000 pixel resolution, to be ablated in a thin film by a single ultrashort pulse.We continue the progress of [1] by reducing the minimum feature size from ~400nm down to <200nm, through careful management of the multiphoton processes, to controllably create connecting structures. Initial results show designed features that are thinner than one-tenth of the laser wavelength. We show that the ability to pattern unique structures for each individual laser pulse enables the patterning of large areas of contiguous complex structures (1mm-squared per hour), with sub-wavelength feature sizes. We will also present recent experimental results on the application of this technique to the rapid parallel processing of bulk materials, including diamond.

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Contributors

Author: B. Mills

Author: J.A. Grant-Jacob

Author: R.W. Eason

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