Ultrashort femtosecond pulse laser (pulse duration 2 nano-micron films (thickness 150–200 nm) are prepared by spin-coating method. Optical limiting test results show that for the ultrashort pulse laser, this film shows increasing transparency at low light intensity, while it shows decreasing transparency at a higher light intensity (optical limiting). It is capable of changing the optical limiting threshold by changing the incident wavelength which can be used for transparency enhancement and protection against damage of concentrator solar cells. Using this method to have a commercial GaAs solar cells coated found the conversion efficiency reduction 50%.