Making use of focused ion beam as a writting tool. We have been able to transfer patterns with 50 nm resolution. The process is the the following: a) Spin coating of 50 nm of poly-methyl methacrylate (PMMA) on a  Si substrate, b) focused ion beam (FIB) exposure of the pattern, c) development of the imprinted areas, d) pulsed laser deposition of substoichiometric VO_1.7 amorphous thin film, e) lift-off of the film along the remaining organic layer but leaving the array of VO_1.7 nanoparticles and, f) thermal oxidation of the nanoparticles to thermochromic VO₂ in 250 mTorr of oxygen at 450 ºC for 20 minutes.

Nanolithography  "Don Quixote" on vanadium oxide on Indium Tin oxide.

a) Diffractive effects from square arrays of VO₂ nanoparticles obtained by scattering of unpolarized white light incident at 45º.  From left to right, the arrays (150 x150 µm²) have 600, 700, 800, 900 nm as inter-particle distances. b) The sample is placed on a heater stage and illuminated by a focused light source. The scattered light by the VO₂ nanoparticles is collected by an optical fiber in confocal objective and analyzed vs. the temperature of the sample. c) Normalized scattered intensity from a VO₂ array (900 nm lattice constant) illuminated with monochromatic light (980 nm wavelength) incident at 75º and collected with a 10x (0.25 NA) objective.  A signal fall of 70 % is observed when crossing from the semiconducting to the metallic phase.