Abstract

We recently described^1,2 a passive broadband optical limiter that exhibited exceptional limiting performance, yet relied only on a refractive thermal nonlinearity for its operation. That optical limiter employed f/5 defocusing optics and a broadband absorbing dye, nigrosin, dissolved in a solvent, carbon disulfide (CS₂), having a large thermal figure of merit. Following the absorption of an intense light pulse by the nigrosin dye, rapid nonradiative relaxation results in strong, localized heating of the CS₂ solution, leading to thermal defocusing and aberration of the beam. As a result, light is deflected outside of the light collection cone defined by the f/5 optics, thereby limiting the energy transmitted to the detector. The figure of merit³ of that limiter, defined as the product of the linear transmission and the ratio of the incident energy at damage to the transmitted energy at damage, was 25.

© 1994 Optical Society of America