Radar-inspired chirped pulse amplification technique of intense lasers——a standard case of military needs spawning fundamental research

Fundamental research areas are usually born out of free exploration of the Nature. However, national needs, especially special needs of wartime, can lead to unexpected emergence of new areas of fundamental research. Ideas and methods in these areas are more likely to generate revolutionary technologies. A standard case is the radar-inspired chirped pulse amplification technique for strong lasers, which was awarded the 2018 Nobel Prize in Physics. Radar was one of the most important military needs in World War II. On the one hand, the searching for new radar-emitting sources led to a series of innovative fundamental researches, including the emergence of masers and subsequently lasers. Lasers then spawned many new fundamental research areas, such as laser cooling. Lasers and laser-based fiber-optic communication technologies have changed the life style of modern humans. On the other hand, the chirped pulse amplification technique of radar systems was transposed to the field of optics, breaking the technical bottleneck of generating strong lasers. And the emergence of strong lasers has spawned another series of new fundamental research areas, such as inertial confinement fusion. This article will demonstrate the traction of strategic needs on the birth of basic research through the introduction of key technologies from radar to laser and the chirped pulse amplification technique.