Zone Plate Fabrication Using a Low Power Femtosecond Laser

With an advantage in photonic integration and device miniaturization, fabrication of micron sized diffractive optical elements has gained attention due to their low volume, light weight and flexible design. We discuss the fabrication of phase zone plates in soda-lime and borosilicate glass using a femtosecond laser, and its characterization. Our technique of fabrication involves a one-step laser direct writing process in comparison to the popular photolithography based micro-structuring. In this work, the femtosecond laser oscillator system is used to successfully fabricate phase zone plate structures at low energies and high repetition rate. In addition to this, a laser induced breakdown spectroscopy (LIBS) study was done to confirm the consistency of glass obtained from different manufacturers through its composition.