Process for depositing and crystallizing a thin layer of organic material by means of a beam of energy

Claim 1

A process for depositing and crystallizing a thin layer of an organic material on a substrate having first and second parallel faces, said deposited and crystallized material having a non-linear optical response, said process comprising the steps of: cold-compacting a monomer powder of said organic material to provide a block of said organic material which is able to diffuse but not absorb the light of a laser beam having the characteristics set forth below; disposing said block adjacent to and in close proximity to the first face of said substrate, said substrate and said block being maintained at ambient temperature, said subtrate being transparent to said laser beam; providing said laser beam as a continuous laser beam, and applying said continuous laser beam to said second substrate face and through said transparent substrate to said compacted powder block, the energy and wavelength of said continuous laser beam being chosen so as to desorb the organic material forming said block, the temperatures induced by the laser on the surface of said block being lower than the melting point of the organic material forming said block; and performing a relative continuous displacement between the substrate and the laser beam in order to sweep said laser beam over determined paths on said second substrate face to enable the desorbed material from said block to be deposited as a polymer on the adjacent first face of the transparent substrate, the polymer thus deposited being crystallized in a polycrystalline form with giant monocrystalline grains, according to said paths, the sweeping of said face comprising several successive paths, the rate of covering between two successive paths being about 80%.