Ukrainian Journal of Physical Optics

Separation of instant and accumulated nonlinear optical responses of dye-doped liquid crystal using Z-scan traces
¹Gayvoronsky V., ¹Garashchenko V., ²Kislenko V., ²Nikolaienko Yu., ¹Yakunin S.

¹Institute of Physics of NASU, 46 Nauka Ave., 03028 Kiev, Ukraine
²Radiophysical Department, National Taras Shevchenko University, 5 Academician Glushkov Ave., Kiev 01022, Ukraine

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A theoretical approach is developed for distinguishing between the instant nonlinear optical response and the photoinduced accumulation effect on the refractive index. This is performed in terms of superposition of different lens transparencies for the known Z-scan technique. For the case of homeotropic liquid 5CB crystal cell doped with anthraquinone dye, we prove a possibility for decomposing consequent irreversible Z-scan traces into the contribution of instant nonlinear optical response, which takes place before the reorientation threshold, and the accumulated photoinduced refractive index variations occurred due to the exposition.

Keywords: liquid crystal, self-focusing, nonlinear optical effect, Gaussian beam, refractive index variation, Z-scan technique

PACS: 61.30.-v, 42.65.-k, 42.70.Df
Ukr. J. Phys. Opt. 8 88-97 doi: 10.3116/16091833/8/2/88/2007
Received: 07.03.2007 After revision: 12.04.2007

REFERENCES

1. Gayvoronsky V, Yakunin S, Nazarenko V, Starkov V and Brodyn M, 2005. Techniques to Characterize the Nonlinear Optical Response of Doped Nematic Liquid Crystals. Mol. Cryst. Liq. Cryst. 426: 231-241.
        doi:10.1080/15421400590891173 http://dx.doi.org/10.1080/15421400590891173
2. Sheik-Bahae M, Said AA, Wei TH, Hagan DJ and Van Stryland EW, 1990. Sensitive measurement of optical nonlinearities using a single beam. IEEE J. Quant. Electron. QE 26: 760-769.
        doi:10.1109/3.53394 http://dx.doi.org/10.1109/3.53394
3. Gayvoronsky VYa, Yakunin SV, Pergamenshchik VM and Nazarenko VG, 2006. Sign inversion of the optical torque on the nematic director enhanced by anthraquinone dye dopants stable to the light action. Laser Phys. Lett. 3: 531-535.
        doi:10.1002/lapl.200610049 http://dx.doi.org/10.1002/lapl.200610049
4. Gayvoronsky V, Yakunin S, Enikeeva V and Ozheredov I, 2006. Selfaction effects of femtosecond laser pulses in dye-doped 5CB liquid crystal. Laser Phys. Lett. 3: 357-361.
        doi:10.1002/lapl.200610010 http://dx.doi.org/10.1002/lapl.200610010
5. Kislenko VI, Stetsyuk VN and Maevskaya OV, 2006. Determination of the lens transmittance of nonabsorbing media using the optical matrix method. Optics and Spectroscopy. 100: 631-635.
        doi:10.1134/S0030400X06040229 http://dx.doi.org/10.1134/S0030400X06040229
6. Gayvoronsky V, Yakunin S, Pergamenshchik V, Nazarenko V, Palewska K, Sworakowski J, Podhorodecki A and Misiewicz J, 2006. Photoluminescence of     Nematic Liquid Crystal Doped with Anthraquinone Dye. Ukr. J. Phys. Opt. 7: 116-123.
        doi:10.3116/16091833/7/3/116/2006 http://dx.doi.org/10.3116/16091833/7/3/116/2006
7. Cognard J. Alignment of Nematic Liquid Crystals and Their Mixtures. London: Gordon and Breach (1982).
8. Kislenko V.I. and Nikolaenko Yu.N. Z-scan investigation of the optical exposition effects. Proc. of the Sixth International Young Scientist`s Conference on Applied Physics, Kyiv, Ukraine, (2006) p.26.
9. Akhmanov S.A. and Nikitin S.Yu. Physical Optics. New York: Oxford University Press (1997).
10. Korn A. and Korn M. Curvature of a Plain Curve. In Mathematical Handbook for Scientists and Engineers. New York: McGraw-Hill (1968), p. 499.
11. Gerrard A. and Burch J.M., Introduction to Matrix Methods in Optics. New York: Dover (1994).

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