Ultrafast Laser Writing of Waveplates in Porous Glass

In this paper, we demonstrate the process of ultrafast femtosecond laser writing of birefringent waveplates in the bulk of nanoporous glass (NPG) and confirm the possibility of its acceleration by an order of magnitude relative to that in silica glass. In situ measurements of birefringent plate retardance were performed for heating and cooling stages in the 20 – 650°C temperature range. Femtosecond laser-written birefringent elements were found to exhibit a greater thermal stability relative to conventional crystal quartz plates under broad temperature variations. The results obtained are of particular interest to those involved in industrial fabrication of laser-written phase optical elements in NPG.