Light-controlled electro-optic power limiter with a Bi(12)SiO(20) crystal

Gaussian-beam-induced photorefractive birefringence and its application to radio-frequency signal excision

For Gaussian-beam-induced optical limiting based on photoconductive field shielding of electro-optic (EO) birefringence, power-limiting notch widths may be accurately determined by considering the power-limiting threshold for the photorefractive crystal where excess charge accumulates. With sufficient optical intensity the space-charge field completely screens the externally applied electric field, and only a small diffusion field remains. The upper limit of light intensity attenuation is the extinction ratio for the combination of polarizers and EO crystal.

Enhanced optical limiting performance of a nonlinear absorber in a solution containing scattering nanoparticles

The optical limiting performance of a water-soluble porphyrin derivative is shown to be improved when small-sized (400-nm-diameter) nonabsorbing polystyrene spheres are added to the solution. The optical limiting enhancement is attributed to absorption of diffusive photons that experience longer light pathways than ballistic photons. The effect is demonstrated for nanosecond laser excitation at 532 nm.