In order to manufacture large-scale photonic devices of various dimensions at a low cost, a number of printing-based patterning techniques have been developed.
Efficiency of liquid crystal displays highly depends on the amount of polarized light emerging from the backlight module. In this paper, a backlight architecture using a nanoimprint wire grid polarizer for polarization recycling is proposed and studied, in which the extraction efficiency of polarized light is the major concern. The backlight module is composed of the stack of a wire grid polarizer, a lenticular array and a light guide plate. The light guide plate features interleaving v-groove and trapezoidal ridge coated with aluminum on the top surface, and scattering dot array on the bottom. The angular divergence of emerging light from the light guide plate can be well constrained so as to exploit the angular range with the best transmission of polarized light for the wire grid polarizer. The prototype of a 2.5-inch module has demonstrated an angular divergence of 48°. The overall extraction efficiency of polarized light enhanced by 21% and uniformity of 76% have been achieved.
We design, fabricate and experimentally demonstrate a compact thermo-optic gate switch comprising a 3.78µm-long coupled L0-type photonic crystal microcavities on a silicon-on-insulator substrate. A nanohole is inserted in the center of each individual L0 photonic crystal microcavity. Coupling between identical microcavities gives rise to bonding and anti-bonding states of the coupled photonic molecules. The coupled photonic crystal microcavities are numerically simulated and experimentally verified with a 6nm-wide flat-bottom resonance in its transmission spectrum, which enables wider operational spectrum range than microring resonators. An integrated micro-heater is in direct contact with the silicon core to efficiently drive the device. The thermo-optic switch is measured with an optical extinction ratio of 20dB, an on-off switching power of 18.2mW, a therm-optic tuning efficiency of 0.63nm/mW, a rise time of 14.8µsec and a fall time of 18.5µsec. The measured on-chip loss on the transmission band is as low as 1dB.Integrated optical switches are important building blocks in silicon photonics. While output-port-selective switches are useful for optical routing applications, optical gate switches with single output port for off-to-on and on-to-off operations also have many potential applications such as optical interconnects and optical logic devices 1,2 . Silicon based optical gate switches have attracted a significant amount of attentions in recent years, due to their small size, large scalability, and potential for integration with wavelength-division-multiplexing (WDM) systems. Since silicon's thermo-optic (TO) effect is significantly larger than its electro-optic (EO) effect, silicon TO switches promises efficient and low-power operation. Conventional MachZehnder interferometers and directional couplers can be used as optical gate switching structures, but they require long waveguides (several millimeters) to obtain π phase shift of light and require relatively high switching power, which limits the integration density and energy conservation 3,4 . Another type of widely-used compact structure for efficient switches a microring resonator. So far, the smallest ring diameter reported is 3µm 5 ; however, one drawback of microring switches is the a
On the purpose of improving the transmittance of LCD panels, the study of polarized illumination has been emphasized as one of the urgent topics to reduce the energy loss at the present absorptiontype polarizer of LCD cells. The polarization-selection property of nano-wire-grid structures has been widely studied for a reflective polarizer and applied to increase the transmittance of LCD. For a determined wire-grid polarizer, the transmittance of P polarization (T p ) depends on wavelength and incident angle. The effective incident angle is limited by total internal reflection (TIR) condition of selected polymer materials for wire-grid substrates. This paper presents a polarized backlight unit consisting of an aperture-limited light-guide plate featured by plurality of aluminum-coated trapezoid ridges on the output surface and a hybrid nano wire-grid which has been proposed to improve the transmittance of LCD by polarization recycling and emission angle control. Gain of central brightness was achieved up to 2.1x. IntroductionThe transmittance of current LCD panels is around 4-7% of the backlight emission mainly caused by the energy absorption of the down polarizer (>50% loss) and the color filter component (>67% loss). On the purpose of improving the transmittance of LCD panels the study of polarized illumination has been emphasized as one of the urgent topics to reduce the energy loss at the present absorption-type polarizer of LCD cells. Thus, the birefringence materials and components exhibiting polarization selection through transmission and reflection mechanism are studied and applied as the reflective polarizer for the LCD panels [1]. With highly flexible design freedom the texture-controllable birefringence property of the nano wire-grid (NWG) component consisting of metal grating or metal-dielectric grating at scale of 100s-200s nm has attracted lots of research works in the past decade. The geometric features of the NWG, like stack orientation, pitch, aspect ratio (AR), and duty cycle (DC), relates directly to its birefringence property denoted mainly by transmission of P polarization (Tp) and transmission of S polarization (Ts) and extinction ratio (Ext.R, defined by the ratio of Tp to Ts). In the edge-lit backlight units, many research works have applied the NWG structure onto the LGP to manipulate the polarization property for the emission light [2,3]. In order to control the angular distribution that determines the total extraction efficiency of P polarization from the NWG and the brightness concentration on the central axis of backlight units as the preferred illumination condition for LC cells the light extraction structure which generally comprises the plurality of micro vgrooves on the surface opposite to the NWG side of the LGP [2-5] is also required. However, it is difficult to fabricate the LGP with two individual structures at extremely different scales using current tooling arts.For the purpose on improving the efficiency of polarization extraction and also considering satisfactory uniformity...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.