Interaction of intense laser light with chiral nematic structure was examined by use of a reflected-probe-beam experimental technique. The technique is sensitive to structural changes in periodic media and appears to be as valuable for chiral nematics investigation as rentgenografic diffraction for crystal lattices. The paper presents partial results of experiment which is just now continued. They suggest optical nonlinearity in chiral nematics of the collective nature rather than of thermal or photochemical origin. The experimental data obtained up to now are discussed in details, although at present some essential questions remain not clear and therefore no theoretical analysis is given.