Optical power limiters for nanosecond pulses: Design of new dendritic chromophores with exceptionally large two-photon cross-sections

Over the past five years there has been a renaissance in design studies of chromophores with the possibility of enhanced two-photon absorption (TPA). While two-photon absorption has been described for molecules such as laser dyes in solution for a number of years', it has only been recently that researchers have attempted detailed structure-property relationships to elucidate how new chromophores with greatly enhanced two-photon cross-sections might be designed. Since the intrinsic cross-sections are related to the Im component of the third order optical nonlinearity, it should come as no surprise that much of the previous work in the Literature which focused on structure-property relationships for molecules with enhanced NLO response might be applicable to the design of new TPA chromophores. In this presentation we will review our recent studies in this area, and our rationale for the applicability of dendritic strctures based on photonic-active repeat units for enhancment of two-photon absorption, particularly in the area of optical power limiting applications.