Lyotropic liquid crystal guest–host material and anisotropic thin films for optical applications

Enhancement of Planar Orientation of Reactive Mesogen Molecules for Optical Retarder Film by Anisotropic Surface Plasma Treatment

“…Crystals 2021, 11, x FOR PEER REVIEW 2 of 14 order parameters than the nematic RM molecules, the homeotropic orientation at the air interface limits their application in the coatable polarizer and in the retarder film [16][17][18].…”

“…Consequently, it is difficult to fabricate a RM retarder film with a uniform orientation of the RM molecules without defects. In particular, the smectic RM molecules that are used for the coatable polarizer often represent a homeotropic orientation at the air interface [16][17][18]. Although the smectic RM molecules show greater order parameters than the nematic RM molecules, the homeotropic orientation at the air interface limits their application in the coatable polarizer and in the retarder film [16][17][18].…”

Engineering the chemical structure of H-shaped reactive molecules for negative dispersion of retardation

“…This idea was experimentally proved by limited groups using copolymers 11–14 and RMs. 15–20 In these days, the single layer approach using RM materials is regarded as a promising solution for future optical components due to their small thickness and simple fabrication process. 15–20…”

“…On the other hand, a negative dispersion (ND) retarder whose Δn increases with longer λ may enable an achromatic response with constant Γ. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Several kinds of approaches have been suggested for the fabrication of ND retarders. The traditional method to make an achromatic retarder is stacking two or more PD retarders.…”

“…9,10 More recently, novel retarder materials have been reported where ND of Δn is achieved using a single layer. [11][12][13][14][15][16][17][18][19][20] The dispersion of refractive index becomes weak as the wavelength of light is farther away from the absorption resonance wavelength. [11][12][13][14][15][16][17][18][19][20] If the material absorbs longer and shorter wavelengths of light along the n e and n o directions, respectively, then n e decreases more than n o with longer λ, resulting in ND of Δn.…”