Optical Evaluation of Geometrical Parameters of Micro-Relief Structures

Abstract

In the present research we have fabricated and investigated two kinds of surface relief gratings (phase diffraction
gratings), formed with standard photolithography combined with the plasma-etching and reactive ion etching (RIE).
Diffraction efficiency of diffraction gratings (originally produced in silicon and quartz glass substrates) was measured
experimentally and estimated using linear dimensions of gratings defined by atomic force microscopy (AFM) and
scanning electron microscopy (SEM). The main experimental results were compared with the computer simulations
where the standard software (“PCGrate 2000MLT” and “GSolver”) were employed to calculate diffraction efficiency of
different period of diffraction gratings for the different wavelengths of visible light. Comparing two evaluation methods:
direct (scanning probe microscopy) and indirect (diffraction efficiency) we have demonstrated feasibility of optical
methods in control of geometrical dimensions of gratings at the microscopic range. These methods enabled us to control
and produce diffraction gratings for the different optical applications, like dispersive elements in spectroscopes, beam
splitters or micro-fluidic devices.