Effect of polymer host on third order nonlinear optical properties of newly synthesized organic liquid crystal

Abstract

We report the investigation of third order optical nonlinearity of 2,4,6-tri-(p-hyptoyoxylphenyl) pyrilium tetraborate doped PMMA using nanosecond laser pulses at 532nm wavelength by employing Z-Scan technique. To see the effect of polymer host, the results have been compared with the pure dopant. The material shows a large negative nonlinearity with real and imaginary parts of χ (3) are -3.31x10 -14 esu and 0.73x10 -14 esu respectively. Excited state absorption cross-section is found to be 3.41x10 -48 cm 4 .s/photon in PMMA host. The magnitude of third order nonlinear parameters increases when the compound is doped into PMMA matrix because of change in the conformation of chain geometry as a result of charge transfer processes. The values are comparable with a best known nonlinear liquid crystal molecule namely, 4-cyano-4'-n-pentylbiphenyl in the nematic phase. Hence, these molecules can be suitably used as nonlinear optical materials in PMMA matrix for device applications.

Nonlinear optical response of liquid crystalline azo‐dendrimer in picosecond and CW regimes

“…The results showed that the nonlinear refractive index in the film was 300 times larger than that in solution. Compared with many other organic materials, such as DDLC, 21 Sudan I, 22 and some organic D‐π‐A compounds, 13 the nonlinear refractive index in LCP was larger. The good nonlinear response of this material indicates it has potential applications in optical devices such as all‐optical switches and modulators.…”