The fabrication of a thin, circular polymer film based phase shaper for generating doughnut modes

We demonstrated the fabrication of a phase shaper for generating a 'doughnut mode' laser beam using a thin, circular polymer film on a substrate. The fabrication method is based on a combination of spin-coating and drop-casting. The alignment procedure to get ideal 'doughnut modes' is described. The intensity distribution at the focus is analyzed with single molecule spectroscopy.