Enhanced Nonlinear Phase-Shift in Epsilon-Near-Zero Materials: The effect of Group and Phase Velocity

Benis, Sepehr; Munera, Natalia; Stryland, Eric W. Van; Hagan, David J.

doi:10.1364/cleopr.2020.c8b_4

Cited by 3 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using BD and Z-Scan measurements, we show that a large NLO phase shift can be achieved at ENZ for combinations of excitation and probe beam wavelengths, while XPM experiments independently validate our results with remarkable agreement. Our findings reveal an extremely large effective NLR consistent with a hot-carrier redistribution mechanism from excitation via photon energies below the bandgap [18,29,30,34].…”

Section: Introductionsupporting

confidence: 57%

“…These materials can exhibit a notable NLO phase shift, 𝛥𝜑, in the vicinity of the ENZ region, manifested by the effective NLR for photon energies below the bandgap [17,19]. Additionally, this extremely large sub-picosecond NLO phase shift may allow obtaining a relatively large spectral shift, 𝛥𝜆, of the incident light [22, 25,28,30]. This simultaneous tunability of both phase and spectrum may be utilized in all-optical signal modulators enabling light-induced switching and frequency synthesizing applications.…”

Section: Introductionmentioning

confidence: 99%

“…This simultaneous tunability of both phase and spectrum may be utilized in all-optical signal modulators enabling light-induced switching and frequency synthesizing applications. Additionally, optically-induced spatial and temporal modifications (space-time tunability) can be used to emulate quantum physical effects allowing the observation of such phenomena in optics [14,22,27,28,30,31].…”

Section: Introductionmentioning

confidence: 99%

“…These descriptions have been shown to provide reasonable insight on the large magnitude of NLR explained via the inverse dependence of the 𝑛 2 coefficient on the linear index, and thus the enhanced NLR at ENZ [1, 17,18,22,23]. We note, however, that the original theories used for explaining the enhancement strictly only apply to bound-electronic nonlinearities while the dominant NLO effect in TCOs has been experimentally shown to be from redistribution of free-carriers [18, 19,29,30,[33][34][35].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Transient Nonlinear Phase-Shift in Epsilon-Near-Zero Materials

Benis

Munera

Stryland

et al. 2020

2020 IEEE Research and Applications of Photonics in Defense Conference (RAPID)

Self Cite

View full text Add to dashboard Cite

Epsilon-near-zero (ENZ) materials have emerged as viable platforms for strong nonlinear optical (NLO) interactions. The NLO phase shift in materials exhibiting an ENZ condition is extremely large, however, direct experimental measurements of the magnitude and time dynamics of this phenomenon, particularly nondegenerate NLO phase shifts, have so far been lacking. Here, we directly measure the NLO phase shift of an Indium-Tin-Oxide (ITO) thin film using three different techniques. By characterizing the excitation-induced, time resolved Beam Deflection (BD) of a probe beam, we measure the nondegenerate NLO effects, allowing a separate determination of the effects of excitation and probe wavelengths on the NLO phase shift as they are varied across the ENZ region. These experiments reveal that having the probe pulse centered at ENZ greatly contributes to this enhancement; however, the NLO phase shift is less sensitive to the excitation wavelength, which only slightly enhances the nonlinearity for obliquely incident TM-polarized light. We also find that the spectral shift of the probe pulse induced by the excitation follows both the magnitude and time dynamics of the NLO phase shift measured via the BD experiments. We observe large, ultrafast cross-phase modulation in agreement with a redistribution of carriers in the conduction band. Finally using the Z-Scan method, we measure the degenerate nonlinear refraction at ENZ near normal incidence. The results of all three measurements agree, revealing a gigantic sub-picosecond NLO phase shift in ITO. At its largest, we consistently measure an effective induced index change that is greater than the linear index.

show abstract

Section: Introductionsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transient Nonlinear Phase-Shift in Epsilon-Near-Zero Materials

Benis

Munera

Stryland

et al. 2020

2020 IEEE Research and Applications of Photonics in Defense Conference (RAPID)

Self Cite

View full text Add to dashboard Cite

show abstract

“…PSILON-NEAR-ZERO (ENZ) materials are a kind of nearzero-index materials [1]. These ENZ materials possess many unique characteristics, such as strong field enhancement [2]- [4], constant phase transmission [5], [6], tunneling through distorted channels [7], [8] and etc. ENZ photonics has attracted extensive attention in recent years, which is considered as a new platform for integrating photonic and nanophotonic devices [9]- [12].…”

Section: Introductionmentioning

confidence: 99%

Optimization of Epsilon-Near-Zero Multilayers for Near-Perfect Light Absorption Using an Enhanced Genetic Algorithm

Wang

et al. 2021

IEEE Photonics J.

View full text Add to dashboard Cite

Using epsilon-near-zero (ENZ) subwavelength optical multilayer materials with simple structure and thin total thickness to achieve target characteristics is extremely important and beneficial for the realization of on-chip integration and largescale application of optical devices. Combining with the enhanced genetic algorithm (EGA), this work breaks the limitation of the periodicity of traditional ENZ multilayer structures, and investigates the aperiodic ENZ transparent conducting oxide (TCO)-dielectric multilayer structures. It is realized that under the given conditions, an optimal structure can possess a maximum peak absorption and the broadest absorption bandwidth near the communication wavelength. In the 6-layer structure with a total thickness of 600 nm studied in this work, EGA can optimize the peak absorption from 0.91 to 0.95. Additionally, the absorption bandwidth is optimized from 120 nm to 227 nm, which is enhanced more than 180%. The absorption performance of this optimized structure is comparable to that of a more complex structure with the same total thickness but more layers, or a structure with the same number of layers but a larger total thickness. Conclusively, the proposed EGA optimization method can simplify the structure of the multilayer system, reduce the total thickness of the required ENZ material, and thus greatly simplify the production process and reduce the production cost.

show abstract

Epsilon-near-zero photonics: infinite potentials

et al. 2021

View full text Add to dashboard Cite

With its unique and exclusive linear and nonlinear optical characteristics, epsilon-near-zero (ENZ) photonics has drawn a tremendous amount of attention in the recent decade in the fields of nanophotonics, nonlinear optics, plasmonics, light-matter interactions, material science, applied optical science, etc. The extraordinary optical properties, relatively high tuning flexibility, and CMOS compatibility of ENZ materials make them popular and competitive candidates for nanophotonic devices and on-chip integration in all-optical and electro-optical platforms. With exclusive features and high performance, ENZ photonics can play a big role in optical communications and optical data processing. In this review, we give a focused discussion on recent advances of the theoretical and experimental studies on ENZ photonics, especially in the regime of nonlinear ENZ nanophotonics and its applications. First, we overview the basics of the ENZ concepts, mechanisms, and nonlinear ENZ nanophotonics. Then the new advancements in theoretical and experimental optical physics are reviewed. For nanophotonic applications, the recent decades saw rapid developments in various kinds of different ENZ-based devices and systems, which are discussed and analyzed in detail. Finally, we give our perspectives on where future endeavors can be made.

show abstract

Enhanced Nonlinear Phase-Shift in Epsilon-Near-Zero Materials: The effect of Group and Phase Velocity

Abstract: We present Beam-Deflection experiments, to measure the temporal and spectral dependence of the nonlinear phase-shift of ITO at ENZ. Our measurements suggest that group and phase velocity contribute to the enhanced nonlinearities observed at ENZ. © 2020 The Author(s)

Cited by 3 publications

References 4 publications

Transient Nonlinear Phase-Shift in Epsilon-Near-Zero Materials

Transient Nonlinear Phase-Shift in Epsilon-Near-Zero Materials

Optimization of Epsilon-Near-Zero Multilayers for Near-Perfect Light Absorption Using an Enhanced Genetic Algorithm

Epsilon-near-zero photonics: infinite potentials

Contact Info

Product

Resources

About