Novel Thermally Stable Polymer Materials for Second-Order Nonlinear Optics

Abstract

A novel method of preparing thermally stable thin films with intrinsic second-order nonlinear optical activity is described. Design and synthesis yielded new ferroelectric bifunctional liquid crystalline acrylate monomer mixtures with a fast electro-optical response in the chiral smectic C (SmC*) phase. The ferroelectric liquid crystalline monomer mixtures were poled and subsequently cross-linked by in-situ photopolymerization in the surface-stabilized ferroelectric liquid crystal state. After cross-linking the polarization is no longer reversible, hence the material is pyroelectric and not ferroelectric. The cross-linked pyroelectric materials displayed a thermally stable nonlinear optical response.

Second-harmonic generation in a novel crosslinked pyroelectric liquid crystal polymer (PLCP)

“…In 1995 the acrylate compounds A1 and A2 repetition rate of 10 Hz, which in the present experiment was set to operate at 1100 nm wavelength. In both cases, (® gure 1) were synthesized, and stable, pyroelectric liquid crystal polymer ( PLCP) networks from mixtures of these one or several visible-cut ® lters were placed in front of the sample allowing only fundamental light to reach the were made which showed second-harmonic generation [19,20 ]. A1 is the chiral monomer, and it is monosample, and an IR-cut ® lter was placed behind the sample, eliminating any remaining fundamental light functional.…”

“…corresponded to the coe cient d33 as being responsible According to equation ( 19) the intensity of the SH for the SHG, but being non-phase matched. light is proportional to the square of the fundamental In order to analyse the measurements and estimate light intensity the non-linear optical coe cients of the polymer A2c, it is convenient to rewrite equations ( 19), ( 20) and ( 25 )…”

Synthesis and Characterisation of Side‐Chain Liquid Crystalline Poly[1‐({[(4‐cyano‐4′‐biphenyl)oxy]alkyl}oxy)‐2,3‐epoxypropane]

“…This arises not only as a result of their properties as materials in a range of advanced electro-optical technologies, [2][3][4][5][6][7][8][9][10] but also because they present a demanding challenge to our understanding of self-assembly in molecular systems. [11][12][13] The main reason is that SCLCPs can combine the unique properties of low-molar mass liquid crystals and polymers, which made it easier to form films during material processing.…”

Ferroelectric liquid crystalline elastomers, 1. Variation of network topology and orientation

“…The value of the piezocoefficient in these systems is strongly dependent on the orientation and geometry of the smectic layers (bookshelf or chevron). High crosslinking densities in the systems result in solids that are no longer able to switch in electric a.c.-fields 8,9,10) . Our successful approach to create smectic-C* elastomers that show piezoelectric effects, too, starts with an orientation of photo-crosslinkable ferroelectric polymers in the electric field.…”