Progress in high power semiconductor lasers

Advances in high power semiconductor laser diodes have resulted in both dramatic demonstrations of laser diode characteristics and of innovative systems designs based on these semiconductor sources. As a measure of the capabilities of the semiconductor laser diodes; monolithic laser diode sources have been fabricated which operate to greater than 120 W CW from a 1 μm by 1 cm emitting aperture. As a result of such high power demonstrations, the application base of laser diodes can be expanded from the low power, few milliwatt, applications to applications that require kilowatts of power. As a result laser diodes have become the visionary technology for almost all laser based systems. The advances in high power laser sources can be roughly categorized into four technology areas; (i) higher power output, (ii) greater reliability, (iii) increased coverage of the spectrum and (iv) the development of high power diffraction limited sources. In addition to the development of high power diode lasers, much of the recent advances include areas of hybrid technologies where the coupling of high power semiconductor laser diodes with complimentary technologies have further advanced the state of the art in laser sources. The following discussions will try to cover the advances in the four categories by reviewing the key demonstrations in the development of high power sources