Laser countermeasures using ultrashort pulses

Ultrashort laser pulses with pulse durations in the femtosecond regime are a research area which has been studied intensively the recent years. Laser systems generating femtosecond pulses are commercially available and are relatively easy to operate. Basically they can be divided into high energy system generating peak power in the terawatt region and smaller systems having lower pulse energy but higher pulse repetition frequency and the capability to emit broadband radiation. The fast technology development makes femtosecond lasers an interesting candidate for different countermeasure applications. Laser pulses in the femtosecond region are associated with new phenomena which can be utilised in laser countermeasures. During propagation in the atmosphere filamentation and broadband radiation can be created at remote distances from the laser source. Another issue of interest considering femtosecond pulses is the possibility to manipulate properties in semiconductor materials providing new means to deteriorate the performance of photodetectors. Laser induced damage is an area of importance where ultrashort pulses create new phenomena which may be employed as countermeasures. Exposing laser protection materials to femtosecond pulses where traditional protection mechanisms may fail is another interesting topic. This report provides a short overview of the possibilities related to the use of femtosecond laser pulses in countermeasure applications. The effects discussed include jamming or dazzling of electro-optical sensors, inducing damage in optical materials or detectors and affecting components used in laser protection applications.