Femtosecond filaments as a new type of laser guide stars for astronomical adaptive optics

Femtosecond laser filament in different air pressures simulating vertical propagation up to 10 km

“…This characteristic is very useful in many applications. Possible applications are guide stars in higher layers of the atmosphere [11], lightning control [10,[12][13][14][15][16] or the detection and identification of atmospheric components using a technology of light detection and ranging (lidar) [17][18][19], and filament induced condensation [20][21][22][23]. For such outdoor applications, it is necessary to study filamentation in air under real atmospheric conditions, including the low-pressure conditions encountered at high altitudes.…”

Spaceborne laser filamentation for atmospheric remote sensing

“…Laser filamentation, resulting from the nonlinear propagation of intense ultra‐short laser pulses in the atmosphere , has become a promising tool in the field of optical remote sensing. Powerful femtosecond laser pulses initiated from the ground can propagate in the atmosphere to deliver intensities of around 10 13 W/cm 2 up to altitudes of 20 km and were proposed for applications ranging from the generation of new laser guide stars for astronomical adaptive optics to the generation of an atmospheric electricity discharge . High pulse intensities lead to a competition between various physical effects including the optical Kerr effect focusing the beam and laser energy absorption, which in turn leads to plasma generation and plasma‐induced beam defocusing.…”