Electrostatic Self-Assembly of Optical Limiting Coatings

Optical limiting materials are needed for eye and sensor protection against laser damage. One promising approach for broadband optical limiting in the visible-near infrared band is to employ filters containing reverse saturable absorbents (RSA). Effective RSA materials absorb weakly in the protected band, but become strongly attenuating when optically excited due to efficient population of highly absorbing excited states. We propose here to design polymers that can be electrostatically self-assembled (ESA) into supramolecular multilayer stacks that provide optical limiting characteristics tailored for laser hardening. The key materials technology on which we will build is that of phase homogeneous RSA-containing polyelectrolytes. This class of compounds will be designed in anionid and cationic forms to provide building locks for electrostatic self-assembly of thin RSA films onto optical substrates. They will further be designed with elastomeric backbones to enhance their thermal dissipation and laser damage threshold. In Phase I we will synthesize two candidate polymers (a metalloporpyrin and metallophthalocyanine anionic polyelectrolyte), demonstrate assembly of robust thin film multilayers on glass, and evaluate their optical limiting and laser damage threshold characteristics.Optical limiting materials are needed for eye and sensor protection against laser damage. One promising approach for broadband optical limiting in the visible-near infrared band is to employ filters containing reverse saturable absorbents (RSA). Effective RSA materials absorb weakly in the protected band, but become strongly attenuating when optically excited due to efficient population of highly absorbing excited states. We propose here to design polymers that can be electrostatically self-assembled (ESA) into supramolecular multilayer stacks that provide optical limiting characteristics tailored for laser hardening. The key materials technology on which we will build is that of phase homogeneous RSA-containing polyelectrolytes. This class of compounds will be designed in anionid and cationic forms to provide building locks for electrostatic self-assembly of thin RSA films onto optical substrates. They will further be designed with elastomeric backbones to enhance their thermal dissipation and laser damage threshold. In Phase I we will synthesize two candidate polymers (a metalloporpyrin and metallophthalocyanine anionic polyelectrolyte), demonstrate assembly of robust thin film mul