Infrared and Laser Engineering, Volume. 54, Issue 7, 20250268(2025)
Research on azo dye thin film polarizer with nano-scale guided-mode resonance structure (invited)
Haonan JIANG1, Zhengui FAN2, Jianbin QIU2, Yuanxing LI3, Yuhuai CHEN4, Manchun TSENG1, Fion YEUNG1, Enguo CHEN1,2,5, and Hoising KWOK1
Author Affiliations
1The State Key Laboratory of Displays and Opto-Electronics, The Hong Kong University of Science and Technology, Hong Kong SAR 999077, China2National & Local United Engineering Laboratory of Flat Panel Display Technology, Fuzhou University, Fuzhou 350011, China3Fujian Huajiacai Co., Ltd., Putian 351111, China4Huaying Technology (Group) Co., Ltd., Fuzhou 350015, China5Fujian Optoelectronic Information Science and Technology Innovation Laboratory (Mindu Innovation Laboratory), Fuzhou 350108, Chinashow less
ObjectiveHigh performance thin film polarizer has become one of the research hotspots in the research of LCD display technology. Compared with wire grid polarizer on the market, it achieves a thickness of less than μm while maintaining high birefringence and being an important component of high contrast ultra-thin LCD displays. Azo dye (AD) anisotropic materials are considered ideal materials for high-performance thin film polarizers used in ultra-thin LCD displays due to their photoinduced steering and strong anisotropic absorption characteristics, which have advantages like simple preparation, thin thickness, and large dichroism ratio (DR).
MethodsThis article builds an FDTD model of AD thin film polarizer for comparing experimental absorption spectrum and simulated absorption spectrum (
Fig.3). Four possible models were constructed based on the different alignments of AD molecules in the thin film layer and the GMR unit, and their DR differences were compared in
Fig.4. Then, we explore the effect on DR performance with the different heights of GMR unit and different thicknesses on thin film layer (
Fig.6 and
Fig.7).
Results and DiscussionsThis paper introduces a nano-GMR structure upon the AD film layer, combining molecular-level anisotropic absorption and structural-level strong resonant absorption to achieve dual absorption enhancement of the AD thin film polarizer. By optimizing the nano-GMR unit and thin film layer thickness, an average DR improvement of 83.3% was achieved compared to a single 150 nm AD film polarizer, where the minimum and maximum values reached 40.5% and 149.5%, respectively, while the overall thickness of the polarizer was only 220 nm. This study provides ideas for the design and preparation of high-performance AD thin film polarizer, which is of great significance in the development of high contrast ultra-thin LCDs.
ConclusionsThis paper introduces the nano-GMR unit into the AD4455 thin film polarizer, which generates molecular anisotropic absorption of linearly polarized light and enhanced absorption of GMR structure. The results showed that by placing nano-GMR unit upon an AD thin film polarizer, DR performance has an average improvement of 54.4% in the wavelength range of 400-550 nm compared to a single AD4455 thin film polarizer, where the minimum and maximum value reach 38.5% and 74.4%, respectively. After further optimization for the thickness of the thin film layer, the final average DR improvement reached 83.3%, where the minimum and maximum values reached 40.5% and 149.5%, respectively. The introduction of this structure significantly enhances the performance of AD-based thin film polarizer, which is of great significance for the integration of high-performance thin film polarizers in ultra-thin LCD displays.