Implementation of interference in a confocal laser scanning microscope and its application for in situ observation of crystal growth processes

It is shown that interference can be implemented in the optical scheme of an Olimpus Lext-3000 laser scanning microscope. The occurring interference patterns are differently localized in space, depending on the experimental conditions. Interference from opposite crystal (volume) faces can be observed under certain conditions, which makes it possible to visualize (with a high sensitivity) defects that are invisible in polarized light and the surface relief. Misorientations and deformations in a crystal can be estimated. Our analysis allowed us to interpret the in situ observed interference pattern from growing lisozyme protein crystals and K₂Co(SO₄)₂ · 6H₂O crystals.