Measurement of the third order nonlinear properties of conjugated polymers embedded in porous silicon and silica

Abstract

oral session 7 " Optical Phenomena & devices " [O-33]International audienceThird order nonlinear properties of new composite materials obtained by embedding conjugate polymers in porous silicon and silica matrices are measured in near infrared. A new technique so-called "I-scan" was used as alternative to the classical z-scan, since better adapted to the particular form of samples. The picoseconds measurements show a significant increase of the nonlinear refractive index not only with respect to the standard optical materials but also to the bulk conjugated polymers. Embedding of PTS, PT12, and PPV in nanopores enhances considerably their already very large nonlinear refraction index and lower their overall absorption due to a negative nonlinear absorption

Nonlinear-Optical Properties of Porous Silicon Nanostructures

“…In I-scan measurements the light intensity is controlled in broad limits by means of optical attenuator, whereas the laser-beam cross section has no variation. [85][86][87][88]…”

Nanocomposites obtained by embedding of conjugated polymers in porous silicon and silica

“…2. The nonlinear refractive index in the composite material was found to be n 2 = 2.7 10 -15 m²/W indicating a self-focusing nonlinearity, about three orders of magnitude stronger than the one of CS 2 [8]. Open aperture transmission measurements show a saturable absorber behavior.…”

“…For the measurement of the third order nonlinearity we used the same technique as described above. Close aperture I-scan measurement gave for the nonlinear refractive index n 2 = 3.8 10 -15 m²/W thus indicating a focusing nonlinearity which is about three orders of magnitude larger than the well known reference CS 2 [8]. Measurements of the nonlinear refractive index of free standing films of PDA-TS for the aim of comparison are actually in progress.…”

Thermo-optical properties of gold nanoparticles in colloidal systems

“…The rise in temperature of the medium is accompanied by a change in its refractive index ( n = (dn/dT ) T ), which alters the propagation of the probe beam. From equation 1it is possible evaluate the dependence between TLS and E in an experiment called Iscan [5,6]. The data provided in this experiment can be linearly fitted in order to obtain the slope, ζ defined by:…”