Induced Local EMP and Secondary THz Radiation in Sensor Window Materials from Intense Femtosecond Pulses at Long Range

When high power femtosecond laser pulses are launched in the air, they self-generate long high intensity filaments over hundreds of meters. The initial near IR laser pulse is transformed into a super broad laser pulse spanning from the UV to the IR. Important DoD and Homeland Defense applications include the remote detection of biological warfare agents as well as jamming sensors. However, for any practical application, it is important to fully understand the physical mechanism of the long-range propagation and the interaction with the optical media. Time Domain Corporation (TDC) proposes a systematic study of the laser pulse propagation under realistic atmospheric conditions including turbulence. To determine optimum conditions, TDC will study laser pulse propagation as a function of initial laser pulse parameters such as pulse width, frequency chirp, pulse energy, beam radius, and wave-front. Measurements at long distances will include energy, beam profile, peak intensity and spectral content of the pulse. Our effort will also include the interaction of intense fs pulses with optical limiters and filters in the visible and near IR region. This work will determine whether the limiters and filters provide adequate protection for eyes and sensors against ultra-wide band intense fs pulses as well as induced THz radiation and higher harmonic generation.