title: Introduction.
abstract: This is a time of significant efforts in the development and investigation of physical and technical problems related to laser diodes (LD) and their applications. During the last few years astonishing progress in the performance of a wide set of parameters has been achieved. The output of laser diode bar on a level of more than 100 watts was demonstrated, different schemes of efficient phase locking have been investigated, and perspective approaches in realization of various optical configurations of LD pumped solid state lasers (SSL) were introduced. At the same time the existing level of development still is far from physical limits. The capability of semiconductor advanced technologies, heat transfer modes realization, and wide spectral range SSL materials development appears to be very promising. The task of this Focus Issue of Optics Express is to show the contemporary status of the above-mentioned problems and to attract the attention of the laser community to the new opportunities with wide range of applications.
authors.forename: V
authors.initials: V
authors.lastname: Apollonov