Photo-excited multi-frequency terahertz switch based on a composite metamaterial structure

Ji, Hongyu; Zhang, Bo; Wang, Guocui; Wang, Wei; Shen, Jingling

doi:10.1016/j.optcom.2017.11.080

Cited by 32 publications

(15 citation statements)

References 22 publications

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“…When σ Ge = 200 000 S/m, Ge is characterized by metal‐like property, and the absorber achieves a single‐band absorption with an absorptivity of 99.99% at 1.3896 THz, as shown by the blue hollow‐circle dash line in Figure . When applying 800 nm pump light, both the Si and Ge blocks are excited, assuming that the change in conductivity of Si and Ge is consistent, a single‐band absorption at 0.8340 THz with an absorptivity of 98.45% can be achieved when σ Si = σ Ge = 1 000 000 S/m, as plotted by red half‐empty triangle dot curve in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…The dielectric spacer is polyimide with a relative dielectric constant of ε = 3.5 and a loss tangent of tan δ = 0.003. The permittivities ε Si and ε Ge of Si and Ge are 11.7 and 16.3, respectively . The conductivities σ Si and σ Ge of Si and Ge can be tuned by pump light at different wavelengths.…”

Section: Structure and Simulationmentioning

confidence: 99%

“…Terahertz wave, which is between infrared and microwave, has been rapidly developed and widely applied in many fields including medicine, biosensor, wireless communication, security, etc . In recent years, many functional terahertz devices have been designed and developed, such as filters, polarization converters, absorbers, modulators, and switches …”

Section: Introductionmentioning

confidence: 99%

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A photoexcited switchable tristate terahertz metamaterial absorber

Yuan

Yang

Tian

et al. 2019

Int J RF Microw Comput Aided Eng

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In this study, we propose a photoexcited tristate terahertz metamaterial absorber which can switch between single-/single-/dual-band absorption modes in terahertz regime. The unit cell of the absorber incorporates two kinds of photosensitive semiconductor materials filled the gaps between four asymmetric right-angle wires and a cross wire. By applying different wavelengths of pump light on the absorber, two kinds of semiconductor materials can be excited to realize single-/single-/dual-band switchable absorption characteristics. The distributions of electric fields and surface currents at absorption peak frequencies under three absorption states are demonstrated to elucidate the switchable mechanism of the proposed absorber. Moreover, the absorption performance of the proposed tristate absorber is discussed under different polarization and incidence angles. The proposed structure is expected to be applied in the terahertz devices such as tunable absorbers, modulators, filters, and switches.

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Section: Resultsmentioning

confidence: 99%

Section: Structure and Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A photoexcited switchable tristate terahertz metamaterial absorber

Yuan

Yang

Tian

et al. 2019

Int J RF Microw Comput Aided Eng

View full text Add to dashboard Cite

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“…A computational study that is based on maximizing the harmonic generation efficiency via a nonlinear programming algorithm is lacking [ 6 , 7 , 8 ]. Experimental studies usually focus on finding new techniques to increase the second and the third harmonic generation efficiency and there are relatively few experimental studies that have demonstrated a minor increase in the harmonic generation or conversion efficiency via certain experimental configurations and setups [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. Some computational studies have focused on increasing the computation efficiency of harmonic generation problems rather than proving that the harmonic generation efficiency itself can actually be increased.…”

Section: Introductionmentioning

confidence: 99%

“…These include the studies mentioned in [ 6 , 7 , 8 ], which have managed to increase the efficiency of the nonlinear Finite-Difference-Time-Domain (FDTD) method by decreasing the dispersion error. The current literature of harmonic generation via nonlinear wave mixing is dominated by increasing the efficiency of the second/third harmonic generation rather than increasing the efficiency of an arbitrary harmonic [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. There are currently no known techniques in the literature that reported a high-efficiency in the microscale for an arbitrary harmonic generation (not necessarily the second harmonic) under monochromatic optical excitation [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 30 , 31 , 32 , 33 , …”

Section: Introductionmentioning

confidence: 99%

High-Fidelity Harmonic Generation in Optical Micro-Resonators Using BFGS Algorithm

2020

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Harmonic generation is an attractive research field that finds a variety of application areas. However, harmonic generation within a medium of micron-scale interaction length limits the magnitude of nonlinear coupling and leads to poor harmonic generation efficiency. In this study, we present a constrained non-linear programming approach based on the Quasi-Newton Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm to obtain high-fidelity harmonic generation in optical micro-resonators. Using this approach, one can achieve high-intensity harmonic generation in a simple Fabry–Perot type optical micro-resonator. The generation of super-intense harmonics at a typical ultraviolet (UV)-ablation frequency of 820 THz and at pure yellow-light (515 THz) is investigated in particular. Moreover, we achieved more than 98% accuracy compared to well-known theoretical results. Our approach enables the design of highly efficient microscale harmonic generators to be used in integrated photonic devices.

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Temperature‐Controlled and Photoexcited Multitasking Janus Metasurface in the Terahertz Region

et al. 2022

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In this paper, a photoexcited multitasking Janus metasurface (MJM) based on the phase‐changed material vanadium dioxide and the photosensitive materials silicon and germanium in the terahertz (THz) region is proposed, which also exploits the directionality feature of electromagnetic waves. The MJM can switch its functionalities between working band shifting and full‐space polarized wave control, and six functions can be implemented by exciting the switchable materials. By regulating the power of the incident pump beam, it is feasible to complete band adjustment in terms of normal incidence, i.e. the band range of polarization conversion ratio >0.9 changing from 1.23 THz–1.91 THz to 0.98 THz–1.91 THz in the reflection state and axial ratio (AR) <3 dB band range toggling between 0.69 THz–1.08 THz and 0.67 THz–0.96 THz in the transmission state. However, for the backward incidence,, it presents reflective linear‐to‐circle (LTC) polarization conversion (PC), with AR <3 dB domain of 0.99 THz–1.63 THz. The multiple reflection interference theory and electric field distributions are introduced to interpret the high performance. Moreover, the designed device exhibits a high angular tolerance for achieving LTC PC. The integration of numerous functions in a single structure endows the MJM with the great benefit for efficient polarization‐controlled applications.

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Photo-excited multi-frequency terahertz switch based on a composite metamaterial structure

Cited by 32 publications

References 22 publications

A photoexcited switchable tristate terahertz metamaterial absorber

A photoexcited switchable tristate terahertz metamaterial absorber

High-Fidelity Harmonic Generation in Optical Micro-Resonators Using BFGS Algorithm

Temperature‐Controlled and Photoexcited Multitasking Janus Metasurface in the Terahertz Region

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