scholarly journals Choice of Polymer Matrix for a Fast Switchable III-V Nanowire Terahertz Modulator

MRS Advances ◽  
2017 ◽  
Vol 2 (28) ◽  
pp. 1475-1480 ◽  
Author(s):  
Sarwat A. Baig ◽  
Jessica L. Boland ◽  
Djamshid A. Damry ◽  
Hoe H Tan ◽  
Chennupati Jagadish ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Modulation Depth ◽  
Areal Density ◽  
Thz Radiation ◽  
Switching Speed ◽  
Parylene C ◽  
Optical Pump ◽  
High Modulation ◽  
Thz Modulator ◽  
Probe Spectroscopy

ABSTRACTProgress in ultrafast terahertz (THz) communications has been limited due to the lack of picosecond switchable modulators with sufficient modulation depth. Gallium arsenide nanowires are ideal candidates for THz modulators as they absorb THz radiation, only when photoexcited – giving the potential for picosecend speed switching and high modulation depth. By embedding the nanowires in a polymer matrix and laminating together several nanowire–polymer films, we increase the areal density of nanowires, resulting in greater modulation of THz radiation. In this paper, we compare PDMS and Parylene C polymers for nanowire encapsulation and show that a high modulation depth is possible using Parylene C due to its thinness and its ability to be laminated. We characterize the modulator behavior and switching speed using optical pump–THz probe spectroscopy, and demonstrate a parylene–nanowire THz modulator with 13.5% modulation depth and 1ps switching speed.

scholarly journals Broadband and high modulation-depth THz modulator using low bias controlled VO_2-integrated metasurface

2017 ◽  
Vol 25 (15) ◽  
pp. 17322 ◽  
Author(s):  
Gaochao Zhou ◽  
Penghui Dai ◽  
Jingbo Wu ◽  
Biaobing Jin ◽  
Qiye Wen ◽  
...  
Keyword(s):  
Modulation Depth ◽  
High Modulation ◽  
Thz Modulator

scholarly journals Terahertz Emission and Ultrafast Carrier Dynamics of Ar-Ion Implanted Cu(In,Ga)Se2 Thin Films

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 411
Author(s):  
Chul Kang ◽  
Gyuseok Lee ◽  
Woo-Jung Lee ◽  
Dae-Hyung Cho ◽  
Inhee Maeng ◽  
...  
Keyword(s):  
Thin Films ◽  
Carrier Dynamics ◽  
Thz Radiation ◽  
Terahertz Emission ◽  
Optical Pump ◽  
Carrier Scattering ◽  
Ultrafast Carrier ◽  
Probe Spectroscopy ◽  
Surge Current ◽  
Ion Implanted

We investigated THz emission from Ar-ion-implanted Cu(In,Ga)Se2 (CIGS) films. THz radiation from the CIGS films increases as the density of implanted Ar ions increases. This is because Ar ions contribute to an increase in the surface surge current density. The effect of Ar-ion implantation on the carrier dynamics of CIGS films was also investigated using optical pump THz probe spectroscopy. The fitted results imply that implanted Ar ions increase the charge transition of intra-and carrier–carrier scattering lifetimes and decrease the bandgap transition lifetime.

Limits of Charge Carrier Transport in Halide Perovskites Revealed by Optical-Pump Terahertz-Probe Spectroscopy

2019 ◽  
Author(s):  
Hannes Hempel ◽  
Andrei Petsiu ◽  
Martin Stolterfoht ◽  
Pascal Becker ◽  
Dieter Neher ◽  
...  
Keyword(s):  
Charge Carrier ◽  
Carrier Transport ◽  
Charge Carrier Transport ◽  
Optical Pump ◽  
Halide Perovskites ◽  
Probe Spectroscopy

Dirac Surface Plasmons in Photoexcited Bismuth Telluride Nanowires : Optical Pump-Terahertz Probe Spectroscopy

Nanoscale ◽  
2021 ◽  
Author(s):  
Mithun K P ◽  
Srabani Kar ◽  
Abinash Kumar ◽  
Victor Suvisesha Muthu Dharmaraj ◽  
Ravishankar Narayanan ◽  
...  
Keyword(s):  
Surface Plasmons ◽  
Bismuth Telluride ◽  
Topological Insulators ◽  
Collective Excitation ◽  
Optical Pump ◽  
Time Resolved ◽  
Mid Infrared ◽  
Plasmonic Materials ◽  
Probe Spectroscopy

Collective excitation of Dirac plasmons in graphene and topological insulators have opened new possibilities of tunable plasmonic materials ranging from THz to mid-infrared regions. Using time resolved Optical Pump -...

Photocarriers dynamics in silicon wafer studied with optical-pump terahertz-probe spectroscopy

2012 ◽  
Vol 285 (20) ◽  
pp. 4102-4106 ◽  
Author(s):  
Gaofang Li ◽  
Dong Li ◽  
Zuanming Jin ◽  
Guohong Ma
Keyword(s):  
Silicon Wafer ◽  
Optical Pump ◽  
Probe Spectroscopy

scholarly journals Neural Rate and Timing Cues for Detection and Discrimination of Amplitude-Modulated Tones in the Awake Rabbit Inferior Colliculus

2007 ◽  
Vol 97 (1) ◽  
pp. 522-539 ◽  
Author(s):  
Paul C. Nelson ◽  
Laurel H. Carney
Keyword(s):  
Inferior Colliculus ◽  
Dynamic Range ◽  
Modulation Depth ◽  
Average Rate ◽  
Modulation Frequency ◽  
Detection Threshold ◽  
Depth Functions ◽  
Depth Discrimination ◽  
High Modulation ◽  
Envelope Processing

Neural responses to amplitude-modulated (AM) tones in the unanesthetized rabbit inferior colliculus (IC) were studied in an effort to establish explicit relationships between physiological and psychophysical measures of temporal envelope processing. Specifically, responses to variations in modulation depth ( m) at the cell’s best modulation frequency, with and without modulation maskers, were quantified in terms of average rate and synchronization to the envelope over the entire perceptual dynamic range of depths. Statistically significant variations in the metrics were used to define neural AM detection and discrimination thresholds. Synchrony emerged at modulation depths comparable with psychophysical AM detection sensitivities in some neurons, whereas the lowest rate-based neural thresholds could not account for psychoacoustical thresholds. The majority of rate thresholds (85%) were −10 dB or higher (in 20 log m), and 16% of the population exhibited no systematic dependence of average rate on m. Neural thresholds for AM detection did not decrease systematically at higher SPLs (as observed psychophysically): thresholds remained constant or increased with level for most cells tested at multiple sound-pressure levels (SPLs). At depths higher than the rate-based detection threshold, some rate modulation-depth functions were sufficiently steep with respect to the across-trial variability of the rate to predict depth discrimination thresholds as low as 1 dB (comparable with the psychophysics). Synchrony, on the other hand, did not vary systematically with m in many cells at high modulation depths. A simple computational model was extended to reproduce several features of the modulation frequency and depth dependence of both transient and sustained pure-tone responders.

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