A method to prepare new polymorphs of materials which have not been observed or to obtain a known polymorph under different conditions than those in which it is usually made by using a laser to cause nucleation and crystal growth to occur in a supersaturated solution in such a way as to obtain a crystal structure which would not normally appear without the use of the laser. For example, laser light can cause spontaneous nucleation of gamma-glycine crystals from a supersaturated aqueous solution.