The Encyclopedia of Laser Physics and Technology is a free online encyclopedia of laser technology [1] and related areas such as optical fibers and ultrashort pulses. Its author is Dr. Rüdiger Paschotta, founder of the consulting firm RP Photonics Consulting GmbH [2] in Bad Dürrheim, Germany. This encyclopedia is also available as a two-volume book at Wiley-VCH (ISBN 978-3-527-40828-3).