Lithography-free high aspect ratio submicron quartz columns by reactive ion etching

We describe lithography-free fabrication of sub-micron surface features on quartz substrates by the reactive ion etching (RIE) in a CF4/Ar atmosphere. These submicron glass columns are well defined, have a high aspect ratio, with the underlying substrate being very flat. The geometry of the fabricated surface columns is dependent on the RIE process parameters. The analysis of these glass columns shows that a differential etching process takes place. The optical characterization of these samples shows a significant absorption at visible wavelengths whereas the relative transmission is very high in the infrared range, suggesting that these samples could potentially be used for wavelength selection device applications.