A streamlined set-up for Lloyd’s mirror interference lithography, using a single-mode-fibre-coupled laser

We describe a streamlined set-up for Lloyd’s-mirror-based laser interference lithography (LM-LIL), using only a fibre-coupled single-frequency laser (SFL), a plane mirror and an optional half-wave plate as the optical components. Using an SFL with a factory-set, pigtailed single mode fibre as the LM-LIL light-source greatly simplifies experimental implementation by removing the usual need to manually align a free-space laser-beam to a pinhole-based spatial filter or external fibre. The resulting system is inexpensive, robust and easy to use, allowing for the straightforward preparation of one- and two-dimensional arrays with pitches down to the sub-220-nm level when using a 405-nm laser. Full details of the experimental set-up are provided, together with a step-by-step description of sample preparation, exposure and subsequent processing.