Interferometric analysis of Self-Phase-Modulation at 10.6µw in a nematic liquid crystal

Year: 2003

Authors: Allaria E., Brugioni S., De Nicola S., Ferraro P., Grilli S., Meucci R., Pierattini G.

Autors Affiliation: Istituto Nazionale di Ottica Applicata, Largo E. Fermi 6, 50125 Firenze, Italy;
Istituto per la Microelettronica e le Microtecnologie del CNR, Sez. di Napoli, Via Diocleziano 328, 80124 Napoli, Italy;
Istituto di Cibernetica “E. Caianiello” del CNR, Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy

Abstract: We describe an interferometric technique based on high precision two- dimensional spatial fringe analysis Fourier method. Such a method is used to investigate the characteristic ring diffraction pattern generated by the self-phase-modulation (SPM) effect induced in nematic liquid crystals (NLC) by an infrared laser beam. The experimental set-up employs a Mach-Zehnder interferometer with a c.w. CO2 laser emitting at 10.6µm and a pyroelectric optoelectronic sensor array to detect the modulated ring pattern intensity distribution formed in the far field by a nematic E-7 sample. An accurate determination of the nonlinear refractive index can be obtained by analyzing the two-dimensional phase distribution of the ring pattern.

Conference title:

KeyWords: Coherent light; Electromagnetic wave diffraction; Fourier transforms; Image sensors; Laser beams; Nematic liquid crystals; Numerical analysis; Pyroelectricity; Refractive index, Interference pattern; Laser intensity; Ring diffraction pattern; Threshold value, Phase modulation
DOI: 10.1117/12.530779

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