Biological Lenses as a Photomask for Writing Laser Spots into Ferroelectric Crystals.

Red blood cells on the surface of a lithium niobate crystal can be used as optical lenses for direct writing of laser-induced refractive index changes. The writing process by such a photomask made of biological lenses is due to the photorefractive effect. Wavefront analysis by a digital holographic microscope is performed for deep and accurate evaluation of local refractive index changes. Different focusing properties can be imprinted on the crystal depending on which type of RBC is employed, discocytes or spherical-like RBCs. The possibility to fix into a solid material the optical fingerprint of the RBCs will have an impact on both diagnostics and cell\material interfacing.