Light Driven Self-Organization

Intriguing phenomena of the appearance of order from chaos under light pumping are investigated in the monograph. This light driven self-organisation takes place due to the fact that each new excitation is generated (recombines) in the field produced by already existing excitations therefore probability of the generation (recombination) at some point and state depends on the spatial distribution and states of the available excitations. As the result spatial and orientational ordering of the excitations raise in random media. Electrons and holes in amorphous semiconductors are separated in space and despite the Coulomb repulsion form electron and hole domains. Due to particle segregation the ordered state is long lived -- up to astronomical long time. Orientational ordering breaks the initial inversional symmetry of a material and may be tested by the appearance of second harmonic signal as it is observed in Ge-doped silica fibres. Self-organised system reveals positive feedback in response to static electric field: oriented excitations amplifies initial filed and result in strong phase matched electric field provided effective second harmonic generation. Light acts like optical piston: it fulfils Sesyphean labour pushing electrons in opposite to electric force direction (current against voltage). This allows to perform all optical poling of glasses. As a signature of self-organised system flicker noise of optical parameters with universal spectrum 1/f is observed.