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Opt Express ; 27(22): 32168-32183, 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31684434


High-birefringence liquid crystal (LC) in ultrathin LCOS panels was adopted to prepare high phase precision (mSTD =λ/50) and phase accuracy (mAPAE% ∼8%) with suppressed pixel-level crosstalk effects. In conjunction with optimized digital driving scheme, the zero order light loss was found directly related to the phase accuracy error. Meanwhile, the world's fastest pure phase modulation LCOS with a response time of ∼0.87 ms at 45 °C was also achieved. The low-temporal flicker (P-P ∼2.0%) with high-speed LC responses was demonstrated by applying new digital driving scheme. Finally, the 4K2 K LCOS-SLM (∼7000 PPI) was evaluated its difficulties and opportunities.

Opt Express ; 25(17): 20466-20476, 2017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-29041727


This study presents the low cost fabrication of flexible white-light-emitting diodes (w-LEDs) with nano-honeycomb-structured phosphor films. Extending the dimensions of the nano-honeycomb structures improved the color uniformity of the flexible samples, and the 950-nm pattern sample demonstrated optimal color uniformity because this nano-pattern exhibited an excellent diffusion ability owing to its pitch size. In addition to color uniformity, the use of this nano-pattern improved the luminous efficiency. The 750-nm pattern exhibited the highest luminous efficiency (235.8 lm/W), which was approximately 7% higher than that exhibited by a non-patterned phosphor film sample. Thus, flexible w-LEDs with nano-honeycomb structure optimization have great potential to be used as next-generation lighting sources.

Opt Express ; 23(3): 3230-5, 2015 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-25836181


We report ultrafast excited state dynamics of zinc phthalocyanine and zinc hexadecafluoro phthalocyanine thin films which have nanorod-like structures. Excitons in the singlet states undergo multi-exponential relaxation processes to the ground state and the singlet lifetime within a few tens of picoseconds is attributed to the diffusion-limited exciton annihilation process. Diffusive migration of the singlet excitons shows the anisotropic lifetimes depending on the polarization of probe beam. Similar anisotropy is observed in the X-ray diffraction data which exhibits long-range alignment of molecular columns along the long axis of nanorod, whereas disordered arrangement in lateral direction to the axis of nanorod.

Appl Opt ; 50(27): 5299-302, 2011 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-21947049


Because of the nonuniform electric field of the in-plane-switching cell in the thickness direction, an accurate and efficient way for evaluating the Kerr constant of blue-phase liquid crystal (BPLC) needs to be developed. This study demonstrates a method for evaluating the Kerr constant by measuring the off-axis-induced retardation (R(th)) change in normal vertical field cells using a commercial polarimeter. The angle-dependent behavior of the R(th) change is observed as an electric-tunable positive C retarder. In this paper, a sigmoid fitting model has been chosen for calculating the Kerr constant for considering the very small intrinsic birefringence of the BPLC.