Design rules for customizable optical materials based on nanocomposites

Werdehausen, Daniel; Staude, Isabelle; Burger, Sven; Petschulat, J.; Scharf, Toralf; Pertsch, Thomas; Decker, Manuel

doi:10.1364/ome.8.003456

Cited by 27 publications

(27 citation statements)

References 34 publications

(21 reference statements)

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“…In fact, the transition between the homogeneous and heterogeneous regimes is not only a fundamental research issue, it also has immense practical relevance for nanocomposites, which could serve as powerful next‐generation optical materials. [ 16–21 ] Since nanocomposites contain distinct nanoscopic scatterers, they are also ideal prototype systems to investigate optical materials in general. This is because atoms or molecules can be treated on equal footing as nanoscopic scatterers, if their optical response is obtained from quantum mechanical simulations and captured in the notion of scattering theory.…”

Section: From Individual Scatterers To a Refractive Indexmentioning

confidence: 99%

“…This is the basis of the so‐called Maxwell–Garnett–Mie effective medium theory (EMT), which can be used to readily estimate a nanocomposite's effective refractive index. [ 17 ] However, the CM equation, on which the EMT is based, relies on two key simplifying assumptions: First, it treats each scatterer as an electric dipole scatterer with a dipole moment of

\vec{p} = α_{scat} {\overset{E}{true}}_{loc}

. Second, it assumes that the local field at the scatterers' positions

({\overset{E}{true}}_{loc})

is, on average, equal to the external field

(false⟨ {\vec{E}}_{loc} false⟩ = {\overset{E}{true}}_{ext})

.…”

Section: Analytical Modeling Of Optical Materialsmentioning

confidence: 99%

“…For this analysis, we use a small particle radius of merely

r_{scat} = 5 nm

to ensure that the nanospheres, in good approximation, act as ideal point dipole scatterers. [ 17 ] For the sake of simplicity, we initially only consider the effective refractive index obtained from transmission

({\overset{n}{true}}_{eff}^{trans})

. Below and in the Supporting Information, we investigate the differences between

n_{eff}^{trans}

n_{eff}^{ref}

n_{eff}^{meta}

and the EMT in detail.…”

Section: The Homogeneous Regime: Bulk Optical Mediamentioning

confidence: 99%

See 2 more Smart Citations

Modeling Optical Materials at the Single Scatterer Level: The Transition from Homogeneous to Heterogeneous Materials

Werdehausen

Santiago

Burger

et al. 2020

Advcd Theory and Sims

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Materials that contain distinct scatterers, for example, nanoparticles, with sizes exceeding 100 nm scatter light heavily and are heterogeneous. In contrast, the atomic or molecular scatterers in conventional optical materials form a homogeneous distribution on the scale of the wavelength. In this paper, the transition between homogeneous and heterogeneous materials is investigated. To this end, a procedure is introduced that allows for retrieving reliable refractive index values from full wave optical numerical simulations of the underlying multibody scattering problem. Using this procedure, it is shown that the concept of an effective refractive index breaks down on multiple levels as a material transitions out of the homogeneous regime. These findings allow for quantifying how novel dispersion‐engineered nanocomposites for bulk optical applications must be designed and show that Maxwell–Garnett‐type effective medium theories are accurate tools for the design of nanocomposites. The procedure can be readily generalized to other types of scatterers, including atoms and molecules and hence guide the design of different kinds of novel materials.

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Section: From Individual Scatterers To a Refractive Indexmentioning

confidence: 99%

\vec{p} = α_{scat} {\overset{E}{true}}_{loc}

. Second, it assumes that the local field at the scatterers' positions

({\overset{E}{true}}_{loc})

is, on average, equal to the external field

(false⟨ {\vec{E}}_{loc} false⟩ = {\overset{E}{true}}_{ext})

.…”

Section: Analytical Modeling Of Optical Materialsmentioning

confidence: 99%

“…For this analysis, we use a small particle radius of merely

r_{scat} = 5 nm

({\overset{n}{true}}_{eff}^{trans})

. Below and in the Supporting Information, we investigate the differences between

n_{eff}^{trans}

n_{eff}^{ref}

n_{eff}^{meta}

and the EMT in detail.…”

Section: The Homogeneous Regime: Bulk Optical Mediamentioning

confidence: 99%

See 1 more Smart Citation

Modeling Optical Materials at the Single Scatterer Level: The Transition from Homogeneous to Heterogeneous Materials

Werdehausen

Santiago

Burger

et al. 2020

Advcd Theory and Sims

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, this only remains true for composite materials, if the inclusions are small enough for scattering to be negligible, which is only the case if the fundamental assumptions of homogeneity and dipolarity are not violated. If these conditions are fulfilled, the material is an "unrestricted effective mediums", in that the effective refractive index of such a material can be used with the same validity as the one of a conventional optical material (table 1) [42]. In this regime, the effective refractive index consequently still allows determining the macroscopic fields both inside and outside of the material using Snell's law and the Fresnel equations.…”

Section: Regime Classificationmentioning

confidence: 99%

“…In this regime, the real part of the effective refractive index can still be used in Snell's law to determine beam's direction, whereas the imaginary part only provides information about how much energy remains within the beam and not about the microscopic origin of the losses. This is why such a material is a "restricted effective medium", in the sense that the effective refractive index only has a restricted validity (table 1) [42].…”

Section: Regime Classificationmentioning

confidence: 99%

Using effective medium theories to design tailored nanocomposite materials for optical systems

Werdehausen

Staude

Burger

et al. 2018

Current Developments in Lens Design and Optical Engineering XIX

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Modern optical systems are subject to very restrictive performance, size and cost requirements. Especially in portable systems size often is the most important factor, which necessitates elaborate designs to achieve the desired specifications. However, current designs already operate very close to the physical limits and further progress is difficult to achieve by changing only the complexity of the design. Another way of improving the performance is to tailor the optical properties of materials specifically to the application at hand. A class of novel, customizable materials that enables the tailoring of the optical properties, and promises to overcome many of the intrinsic disadvantages of polymers, are nanocomposites. However, despite considerable past research efforts, these types of materials are largely underutilized in optical systems. To shed light into this issue we, in this paper, discuss how nanocomposites can be modeled using effective medium theories. In the second part, we then investigate the fundamental requirements that have to be fulfilled to make nanocomposites suitable for optical applications, and show that it is indeed possible to fabricate such a material using existing methods. Furthermore, we show how nanocomposites can be used to tailor the refractive index and dispersion properties towards specific applications.

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Humidity‐Responsive RGB‐Pixels via Swelling of 3D Nanoimprinted Polyvinyl Alcohol

Kim

Yang

et al. 2022

Advanced Science

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Humidity‐responsive structural coloration is actively investigated to realize real‐time humidity sensors for applications in smart farming, food storage, and healthcare management. Here, humidity‐tunable nano pixels are investigated with a 700 nm resolution that demonstrates full standard RGB (sRGB) gamut coverage with a millisecond‐response time. The color pixels are designed as Fabry–Pérot (F–P) etalons which consist of an aluminum mirror substrate, humidity‐responsive polyvinyl alcohol (PVA) spacer, and a top layer of disordered silver nanoparticles (NPs). The measured volume change of the PVA reaches up to 62.5% when the relative humidity (RH) is manipulated from 20 to 90%. The disordered silver NP layer permits the penetration of water molecules into the PVA layer, enhancing the speed of absorption and swelling down to the millisecond level. Based on the real‐time response of the hydrogel‐based F–P etalons with a high‐throughput 3D nanoimprint technique, a high‐resolution multicolored color print that can have potential applications in display technologies and optical encryption, is demonstrated.

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Design rules for customizable optical materials based on nanocomposites

Cited by 27 publications

References 34 publications

Modeling Optical Materials at the Single Scatterer Level: The Transition from Homogeneous to Heterogeneous Materials

Modeling Optical Materials at the Single Scatterer Level: The Transition from Homogeneous to Heterogeneous Materials

Using effective medium theories to design tailored nanocomposite materials for optical systems

Humidity‐Responsive RGB‐Pixels via Swelling of 3D Nanoimprinted Polyvinyl Alcohol

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