Microgratings fabricated with laser-induced plasma-assisted deposition and laser subtractive patterning

Laser-induced plasma-assisted deposition (LIPAD) is an efficient and low-cost method for processing thin films on transparent substrates, but it is difficult to control in terms of edge evenness, chemical composition homogeneity, and geometric precision. Here, a donor target of stainless steel 316 is used in the LIPAD process to fabricate a homogenous thin film on a glass plate. The effects of laser parameters on the structural and chemical characteristics of the films are systematically investigated. The experimental results show that the density of spherical particles reduces and the particle size shrinks as laser scanning distance increases. The influence of laser scanning distance on the chemical structures of LIPAD films is studied by Raman spectroscopy and x-ray diffraction. Microgratings with precisely defined size are fabricated from the LIPAD thin films by a laser subtractive patterning step, and grating constants retrieved from the optical diffraction experiment match well with the measured strip spacing, envisioning the feasibility of LIPAD in efficient production of microgratings.