Graduate School in Nonlinear Science

Sponsored by the Danish Research Academy





MIDIT                               OFD                           CATS
Modelling, Nonlinear Dynamics       Optics and Fluid Dynamics     Chaos and Turbulence Studies
and Irreversible Thermodynamics     Risø National Laboratory      Niels Bohr Institute and 
Technical University of Denmark     Building 128                  Department of Chemistry
Building 321                        P.O. Box 49                   University of Copenhagen 
DK-2800 Lyngby                      DK-4000 Roskilde              DK-2100 Copenhagen Ø
Denmark                             Denmark                       Denmark

2 lectures

by N. Kukhtarev
Physics Department
Alabama A&M University
USA

MIDIT-seminar 454

Thursday June 24, 1999, 14.00-16.00 h
at MIDIT, IMM Building 305, room 027



Lecture 1: REAL-TIME HOLOGRAPHY: FUNDAMENTALS AND APPLICATIONS

Abstract: Real-time (or dynamic) holography (RTH) is a new synergetic field of modern physics that emerged from nonlinear optics, material science and traditional holography. Physical basis of RTH is interaction of intense inhomogeneous irradiation with recording materials ( as example in photosensitive semiconductors, dielectrics, polymers, biological solutions). Theoretical interpretation of RTH is based mainly on the challenging nonlinear Maxwell-Photorefractive system of equations, that is the source of variety of spatio-temporal patterns. Applications of RTH for an optical processing, 4-dimenstional displays, laser beam shapćing, optical data storage and material characterization will be briefly discussed.

Lecture 2: TRANSVERSE SPATIO-TEMPORAL PATTERNS PHOTOINDUCED BY LASER BEAMS IN ELECTROOPTIC MATERIALS

Abstract: We will discuss formation of the transverse spatio-temporal patterns during interaction of laser beams with photosensitive electrooptic crystals.. Rotating hexagonal patterns were observed in ferroelectric crystals KNbO3 and Ba TiO3 with low-power CW lasers. Interesting phenomenon of spatial subharmonic generation with dynamic space-charge domains was observed during holographic grating recording in photorefractive crystals Bi12SiO20. Both types of patterns will be analyzed based on the nonlinear system of Maxwell-Photorefactive equations. Contribution of optical and space-charge fields in the pattern formation will be compared.