Nonlinear optical characteristics of albumin and collagen dispersions with single-walled carbon nanotubes

The interaction of laser radiation with aqueous dispersion of only bovine serum albumin (BSA) 25 wt. %, only bovine collagen (BC) 2 wt. %, and 25 wt. % BSA with single-walled carbon nanotubes (SWCNTs) 0.3 wt. % and 2 wt. % BC with 0.3 wt. % SWCNT was studied. The beam was absorbed mainly by nanotubes, that confirmed by the small value of the nonlinear absorption coefficients for aqueous dispersed media with BSA 6 cm·GW^-1 , as well as dispersion with BK 4 cm·GW^-1 and the large values of coefficients for these media with addition of SWCNTs, respectively 350 cm·GW^-1 and 70 cm·GW^-1 . Determination of nonlinear optical parameters was obtained by the method of fixed sample location. Knowledge of the values of these parameters allowed calculating theoretical curve of Z-scan with open aperture what made possible to compare with the experimental data.