Abstract-Active bidirectionally controlled terahertz interference fringe shift in DMSO-doped PEDOT:PSS film

Applied Physics Letters

Jingyu Liu, Bin Liu, Dandan Liu, Luyao Xiong, Jingling Shena, Bo Jingyu Liu, Bin Liu, Dandan Liu, Luyao Xiong, Jingling Shena,  Bo Zhanga

https://aip.scitation.org/doi/abs/10.1063/5.0011845

An active bidirectionally controlled terahertz interference fringe shift in a dimethyl sulfoxide (DMSO)-doped poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) film structure was investigated. An interference phenomenon that occurred as a result of wavefront segmentation in a THz time-domain spectroscopy (THz-TDS) system was observed. This THz interference fringe spectrum can be modulated bidirectionally through application of a bias voltage and laser irradiation in terms of its both THz amplitude and interference fringe peaks. The refractive index of the film has an effect on the frequency domain and causes both optical path enhancement and a change in the interference period. THz interference fringes with an electrically induced blueshift and with a photo-induced redshift were acquired.

Abstract-An in situ rewritable electrically-erasable photo-memory device for terahertz waves

Luyao Xiong, Bin Liu, Dandan Liu, Longfeng Lv, Yanbing Hou, Jingling Shen, Bo Zhang

https://pubs.rsc.org/en/Content/ArticleLanding/2020/NR/C9NR08826A#!divAbstract

A terahertz read-only in situ electrically-erasable rewritable photo-memory device based on a perovskite:Ag (perovskite with Ag nanoparticles added)/SnO2/PEDOT:PSS hetero-junction structure is reported. Under low optical excitation, considerable terahertz amplitude modulation in a perovskite:Ag/PEDOT:PSS hybrid structure was achieved. When a SnO2 nanoparticle film was inserted between the perovskite and PEDOT:PSS layer, the attenuation of the terahertz signal was weaker than that of the perovskite:Ag/PEDOT:PSS hybrid structure; however, the SnO2 nanoparticle film considerably prolonged the recovery time of the modulated terahertz wave in air after photo-excitation was stopped. In addition, when bias voltages were applied to the perovskite:Ag/PEDOT:PSS and perovskite:Ag/SnO2/PEDOT:PSS hybrid structures, respectively, the terahertz signals recovered rapidly for both structures. Consequently, the photo-memory functionality was achieved based on a perovskite:Ag/SnO2/PEDOT:PSS hybrid structure with an in situ method for erasing stored information.

Abstract-Terahertz read-only multi-order nonvolatile rewritable photo-memory based on indium oxide nanoparticles

Applied Physics Letters

Hongyu Ji, Wei Wang, Luyao Xiong, Dandan Liu, Longfeng Lv, Bo Zhang, Jingling Shen,

(a) Schematic of the terahertz time-domain spectroscopy (THz-TDS) system. (b) Absorption spectrum and scanning electron microscopy (SEM) image of the indium oxide sample

https://aip.scitation.org/doi/abs/10.1063/1.5051029

We investigate terahertz (THz) read-only multi-order nonvolatile rewritable photo-memory based on indium oxide (In2O3) nanoparticles. Optical excitation of an In2O3/quartz sample increases its conductivity, which attenuates its THz transmission. When the optical excitation is terminated, the modulated THz transmission can recover back to its original value in air. However, the THz transmission shows no obvious change over a long-term when In2O3/quartz is encapsulated in an inert gas (nitrogen). Multi-order nonvolatile digital information storage is obtained at different light intensities, and the photo-memory can be rewritten after thermal annealing. Different THz transmissions are used as coded signal units, which are programmed to store information. These results show that THz read-only multi-level nonvolatile rewritable photo-memory can be realized.

Abstract-Active bidirectional electrically-controlled terahertz device based on dimethyl sulfoxide-doped PEDOT:PSS

Wei Wang, Hongyu Ji, Dandan Liu, Luyao Xiong, Yanbing Hou, Bo Zhang, and Jingling She

Fig. 3 (a) Setup for measurement of the signals of the modulated THz beam based on THz-TDS. (b) Measured signals of the modulated THz beam when the bias is positive (red line) and negative (blue line) for the MPSP sample.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-20-25849

A high-efficiency active bidirectional electrically-controlled terahertz device based on DMSO-doped PEDOT:PSS with low-power photoexcitation is investigated. Under low-power optical excitation of 30 mW (0.5 W/cm2) and under bias voltages ranging from −0.6 V to 0.5 V, spectrally broadband modulation of THz transmission over a range from −54% to 60% is obtained over the frequency range from 0.2 to 2.6 THz in a MEH-PPV/PEDOT:PSS:DMSO/Si/PEDOT:PSS:DMSO hybrid structure. By considering the combined carrier density characteristics of the proposed device, it is found that the large-scale amplitude modulation can be ascribed to the electrically-controlled carrier density in the silicon layer with the assistance of the p-n junction that consists of the DMSO-doped PEDOT:PSS and silicon. Bidirectional modulation has a larger modulation range and is easier to use in communications applications when compared with unidirectional modulation. These results show great potential for application to the design of active broadband terahertz devices.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Optically tunable terahertz-band interference fringes shift

Dandan Liu, Bo Zhang, Wei Wang, Hongyu Ji, Guocui Wang, Jingling Shen

https://www.sciencedirect.com/science/article/abs/pii/S0030401818303602


Optically tunable terahertz (THz)-band interference fringes shift in a polymer/silicon structure was investigated. We report an interference phenomenon formed by partial-through measurements and shift of periodic peaks in a terahertz time-domain spectroscopy system. When the terahertz beam passes through the sample edge, equally-spaced interference fringes are obtained in the frequency domain, and the interference fringes can be varied using an external continuous wave laser. This work offers the ability to observe THz-band interference fringes in the frequency domain; these interference fringes change with variations in the applied excitation light intensity