Foreword

The monograph concerns liquid crystal devices for modulation and switching of light. It presents rather seldom approach to the problem of liquid crystals application. Mostly, in such publications, devices for information visualization are considered, perhaps because such devices create the main segment of liquid crystals market.

The work of Professor Jaroszewicz and his coworkers concerns a more specific, sophisticated constructions, devoted to modification of various parameters of light beams. The work delivers detailed descriptions of devices dedicated to three kinds of light modification. First of them is the change of polarization state of the light beam, mostly used in pathfinders. The second one represents an electrically tuned optical filter that finds application in the detection and measurement of air pollution. The third kind of light modification device is, in principle, a quick light shutter, used first of all in welding helmets. Each of the mentioned devices modifies another parameter of the light beam: state of polarization, spectral range or transmitted light intensity. All these devices are precisely described in the review, starting with the operation principle, technical demands, design scheme and measuring methods of physical and technical parameters. A rich choice of relevant liquid crystalline materials is presented. The authors proposed many application mixtures that combined with different liquid crystal cells allowed them the construction of prototypes with unprecedented characteristics.

The presented monograph is a very useful work addressed to the scientists dealing with both basic research and liquid crystal technology. It can be useful for technicians and students as well.