Title :
Interplay between self-focusing and multiphoton absorption: beam distortion and Z-scan measurements
Author :
Polyakov, S. ; Yoshino, F. ; Stegeman, G.
Abstract :
Summary form only given. Single crystals of polydiacetylene PTS have experimentally shown unique nonlinear optical properties. Four photon absorption (4PA) is very large, (/spl alpha//sub 4/ = 0.25 /spl plusmn/ 0.05 cm/sup 5//GW/sup 3/) at 1600 nm. Furthermore, PTS has a large non-resonant intensity-dependent refractive index coefficient, leading to self-focusing (SF), (n/sub 2/ = [4.0 /spl plusmn/ 0.5] /spl middot/10/sup -4/ cm/sup 2/ /GW). This offers a unique opportunity to study nonlinear beam propagation in regimes previously unavailable experimentally. Large SF occurs already at the distances about 300-500 microns with peak input intensities of several GW/cm/sup 2/. We investigated the interplay between multiphoton absorption and SF, which results in severe beam distortion and affects 4PA Z-scan measurements on relatively thick samples.
Keywords :
multiphoton processes; optical polymers; optical self-focusing; refractive index; 1600 nm; 300 to 500 micron; PTS; Z-scan measurements; four photon absorption; large nonresonant intensity dependent refractive index coefficient; nonlinear beam propagation; nonlinear optical properties; peak input intensities; polydiacetylene; self-focusing; Absorption; Distortion measurement; Nonlinear distortion; Nonlinear optics; Optical distortion; Optical refraction; Optical variables control; Photonic crystals; Refractive index; Thickness measurement;
Conference_Titel :
Quantum Electronics and Laser Science Conference, 2001. QELS '01. Technical Digest. Summaries of Papers Presented at the
Conference_Location :
Baltimore, MD, USA
Print_ISBN :
1-55752-663-X
DOI :
10.1109/QELS.2001.962191
