Q & A EXPERIMENT TO SEARCH FOR VACUUM DICHROISM, PSEUDOSCALAR–PHOTON INTERACTION AND MILLICHARGED FERMIONS

A number of experiments are underway to detect vacuum birefringence and dichroism — PVLAS, Q & A, and BMV. Recently, PVLAS experiment has observed optical rotation in vacuum by a magnetic field (vacuum dichroism). Theoretical interpretations of this result include a possible pseudoscalar–photon interaction and the existence of millicharged fermions. Here, we report the progress and first results of Q & A (QED [quantum electrodynamics] and Axion) experiment proposed and started in 1994. We use a 3.5-m high-finesse (around 30,000) Fabry–Perot prototype detector extendable to 7-m with the cavity mirrors suspended using X-pendulum-double pendulums. To polarize the vacuum, we use a 2.3-T dipole permanent magnet rotated at 5–10 rev/s, with 27-mm-diameter clear borehole and 0.6-m field length. Our ellipsometer/polarization-rotation-detection-system is formed by a pair of Glan–Taylor type polarizing prisms with extinction ratio lower than 10-8 together with a polarization modulating Faraday Cell with/without a quarter wave plate. Our first results give (-0.2 ± 2.8) × 10-13 rad/pass with 18,700 passes through a 2.3 T 0.6 m long magnet for vacuum dichroism measurement. We present our experimental limit on pseudo-scalar-photon interaction and millicharged fermions.

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AXION SEARCH WITH Q & A EXPERIMENT

Modern Physics Letters A ◽

10.1142/s0217732310000149 ◽

2010 ◽

Vol 25 (11n12) ◽

pp. 983-993 ◽

Cited By ~ 18

Author(s):

◽

HSIEN-HAO MEI ◽

WEI-TOU NI ◽

SHENG-JUI CHEN ◽

SHEAU-SHI PAN

Keyword(s):

Magnetic Field ◽

Dark Matter ◽

Quantum Electrodynamics ◽

Galactic Evolution ◽

Historical Account ◽

Photon Interaction ◽

Optical Sensitivity ◽

Fabry Perot ◽

First Results ◽

532 Nm

Dark matter is a focused issue in galactic evolution and cosmology. Axion is a viable particle candidate for dark matter. Its interaction with photon is an effective way to detect it, e.g., pseudoscalar-photon interaction will generate vacuum dichroism in a magnetic field. Motivated to measure the QED vacuum birefringence and to detect pseudoscalar-photon interaction, we started to build up the Q & A experiment (QED [Quantum Electrodynamics] and Axion experiment) in 1994. In this talk, we first give a brief historical account of planet hunting and dark matter evidence. We then review our 3.5 m Fabry-Perot interferometer together with our results of measuring vacuum dichroism and gaseous Cotton-Mouton effects. Our first results give (-0.2 ± 2.8) × 10-13 rad/pass, at 2.3 T with 18,700 passes through a 0.6 m long magnet, for vacuum dichroism measurement. We are upgrading our interferometer to 7 m arm-length with a new 1.8 m 2.3 T permanent magnet capable of rotation up to 13 cycles per second. We aim at [Formula: see text] optical sensitivity with 532 nm cavity finesse around 100,000. When achieved, vacuum dichroism would be measured to 8.6 × 10-17 rad/pass in about 50 days, and QED birefringence would be measured to 28%.

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Design and Measurement of a Terahertz Large-Aperture Quarter-Wave Plate with Double-layer Metal Cut Wires on a Flexible and Thin Film

IEEJ Transactions on Sensors and Micromachines ◽

10.1541/ieejsmas.135.478 ◽

2015 ◽

Vol 135 (11) ◽

pp. 478-479

Author(s):

Takehito Suzuki ◽

Ryuji Ohuchi ◽

Nozomu Koja ◽

Koki Ishihara

Keyword(s):

Thin Film ◽

Double Layer ◽

Quarter Wave Plate ◽

Wave Plate ◽

Large Aperture ◽

Quarter Wave

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Broadband In-Cell Quarter Wave Plate using a Combination of Solution-processed Self-aligning Liquid Crystal Polymer by Coating Technique and Photoalignment

Proceedings of the International Display Workshops ◽

10.36463/idw.2019.0314 ◽

2019 ◽

pp. 314

Author(s):

Zhibo SUN ◽

Zhengnan YUAN ◽

Abhishek Kumar Srivastava ◽

Hoi-Sing KWOK

Keyword(s):

Liquid Crystal ◽

Liquid Crystal Polymer ◽

Quarter Wave Plate ◽

Solution Processed ◽

Coating Technique ◽

Wave Plate ◽

Crystal Polymer ◽

Quarter Wave

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None sharp corner localized surface plasmons resonance based ultrathin metasurface single layer quarter wave plate

Scientific Reports ◽

10.1038/s41598-021-88540-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Qinyu Qian ◽

Pengfei Liu ◽

Li Fan ◽

Liang Zhao ◽

Chinhua Wang

Keyword(s):

Surface Plasmons ◽

Amplitude Ratio ◽

Single Layer ◽

Quarter Wave Plate ◽

Localized Surface Plasmons ◽

Sharp Corner ◽

Wave Plate ◽

Nanophotonic Devices ◽

Elliptical Ring ◽

Quarter Wave

AbstractWe report on a non-sharp-corner quarter wave plate (NCQW) within the single layer of only 8 nm thickness structured by the Ag hollow elliptical ring array, where the strong localized surface plasmons (LSP) resonances are excited. By manipulating the parameters of the hollow elliptical ring, the transmitted amplitude and phase of the two orthogonal components are well controlled. The phase difference of π/2 and amplitude ratio of 1 is realized simultaneously at the wavelength of 834 nm with the transmission of 0.46. The proposed NCQW also works well in an ultrawide wavelength band of 110 nm, which suggests an efficient way of exciting LSP resonances and designing wave plates, and provides a great potential for advanced nanophotonic devices and integrated photonic systems.

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High-Contrast and Scattering-Type Transflective Liquid Crystal Displays Based on Polymer-Network Liquid Crystals

Polymers ◽

10.3390/polym12040739 ◽

2020 ◽

Vol 12 (4) ◽

pp. 739 ◽

Cited By ~ 1

Author(s):

Cheng-Kai Liu ◽

Wei-Hsuan Chen ◽

Chung-Yu Li ◽

Ko-Ting Cheng

Keyword(s):

Liquid Crystal ◽

Polymer Network ◽

Liquid Crystal Displays ◽

Quarter Wave Plate ◽

High Contrast ◽

Trade Off ◽

Twisted Nematic ◽

Quarter Wave ◽

The Common ◽

Linear Polarizer

The methods to enhance contrast ratios (CRs) in scattering-type transflective liquid crystal displays (ST-TRLCDs) based on polymer-network liquid crystal (PNLC) cells are investigated. Two configurations of ST-TRLCDs are studied and are compared with the common ST-TRLCDs. According to the comparisons, CRs are effectively enhanced by assembling a linear polarizer at the suitable position to achieve better dark states in the transmissive and reflective modes of the reported ST-TRLCDs with the optimized configuration, and its main trade-off is the loss of brightness in the reflective modes. The PNLC cell, which works as an electrically switchable polarizer herein, can be a PN-90° twisted nematic LC (PN-90° TNLC) cell or a homogeneous PNLC (H-PNLC) cell. The optoelectric properties of PN-90° TNLC and those of H-PNLC cells are compared in detail, and the results determine that the ST-TRLCD with the optimized configuration using an H-PNLC cell can achieve the highest CR. Moreover, no quarter-wave plate is used in the ST-TRLCD with the optimized configuration, so a parallax problem caused by QWPs can be solved. Other methods for enhancing the CRs of the ST-TRLCDs are also discussed.

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