Nonlinear Absorbers Based on Composites of Multi-Walled Carbon Nanotubes for the Protection of Sensitive Elements of Optoelectronic Systems and Organs of Vision

To create a laser protection device based on nonlinear optical effects, new materials with a high effective nonlinear absorption coefficient are needed. Such an increase is possible if the effects that are characteristic of phthalocyanines and carbon nanotubes are combined. In the case of composites of multi-walled carbon nanotubes (MWCNTs) with a conjugate of lowsymmetry monophthalocyanine with a cyclotriphosphazene, photoinduced electron and energy transfer between dyes and MWCNTs can also be added to this effect and to the effect of nonlinear scattering. This work shows that the value of the effective nonlinear absorption coefficient is influenced by the size of the composites, which was controlled by dynamic light scattering directly in the liquid. Changing the hydrodynamic radius from 148 to 139 nm leads to an increase the effective nonlinear absorption coefficient from 249 to 268 cmoGW ⁻¹ • The composite is an effective absorber and can be used to increase the threshold of irreversible damage to the organs of vision, CCD and CMOS matrices. By placing such a material in focus between two lenses, during the passage of laser radiation with a wavelength of 532 nm, it is attenuated for all values of the total pulse energy exceeding the threshold value.