Free space optical communications using 9-10 fs pulses was investigated through aerosol clouds
approaching 104 to 105 particles per cm3 in a 15 cm long tube containing aerosol particles 4-5 μm in
diameter. This small size is representative of the most difficult situation for the transmission of light
through the atmosphere. The ultra fast pulse transmission were compared to continuous wave (cw)
transmission through the exact same aerosols clouds and compared to the ultra short pulses. Results
indicate that there was increased transmission for the ultra short laser pulses, but was not as high as
expected. The results now can be explained by a recent paper demonstrating that deviation from the Beer
Lambert law does not occur until the ultra short pulse transverses a longer path length in water. Results
will be presented on the pulse dispersion in water and glass.
Inspired by previous theoretical work, experiments on diffraction of 10 femtosecond ultrashort pulses passing through a single slit have been performed. Fringes are dramatically reduced or even eliminated in the diffraction of 10 fs ultrashort pulsed laser in the near field compared with that of the continuous-wave laser. This can be explained in the frequency domain as a result of the broadband spectrum contained in ultrashort pulses. Simulations are performed for Fresnel diffraction for both 10 fs ultrashort pulsed and continuous-wave lasers and the results agree with the experimental observation. The results of this work have important implication in biomedical imaging and remote imaging applications to name only a few.