Enhanced reflection from inverse tapered nanocone arrays

Kong, Xiang‐Tian; Butt, Haider; Yetisen, Ali K.; Kangwanwatana, Chuan; Montelongo, Yunuen; Deng, Sunan; Vasconcellos, Fernando da Cruz; Qasim, Malik M.; Wilkinson, Timothy D.; Dai, Qing

doi:10.1063/1.4892580

Cited by 24 publications

(15 citation statements)

References 11 publications

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“…The formalism developed, moreover, is general and can be used to study other effects associated with resonant particles at interfaces [58][59][60]. For example, instead of conditions for antireflection, one can derive conditions for enhanced or perfect reflection [61][62][63][64][65]. Finally, Eq.…”

Section: Discussionmentioning

confidence: 99%

Condition for perfect antireflection by optical resonance at material interface

Wang¹,

Yu²,

Sandhu³

et al. 2014

Optica

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Reflection occurs at an air-material interface. The development of antireflection schemes, which aims to cancel such reflection, is important for a wide variety of applications including solar cells and photodetectors. Recently, it has been demonstrated that a periodic array of resonant subwavelength objects placed at an air-material interface can significantly reduce reflection that otherwise would have occurred at such an interface. Here, we introduce the theoretical condition for complete reflection cancellation in this resonant antireflection scheme. Using both general theoretical arguments and analytical temporal coupled-mode theory formalisms, we show that in order to achieve perfect resonant antireflection, the periodicity of the array needs to be smaller than the free-space wavelength of the incident light for normal incidence, and also the resonances in the subwavelength objects need to radiate into air and the dielectric material in a balanced fashion. Our theory is validated using first-principles full-field electromagnetic simulations of structures operating in the infrared wavelength ranges. For solar cell or photodetector applications, resonant antireflection has the potential for providing a low-cost technique for antireflection that does not require nanofabrication into the absorber materials, which may introduce detrimental effects such as additional surface recombination. Our work here provides theoretical guidance for the practical design of such resonant antireflection schemes.

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Section: Discussionmentioning

confidence: 99%

Condition for perfect antireflection by optical resonance at material interface

Wang¹,

Yu²,

Sandhu³

et al. 2014

Optica

View full text Add to dashboard Cite

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“…The search for sensing, quantification and readout within a single equipment-free assay will play a greater role in future diagnostics. These attributes may include user-friendly, fool-proof, text/quantity-reporting capabilities and unexplored sensing mechanisms such as paramagnetic particles, quantum dots, coloured latex particles, and genetically engineered whole cells based on synthetic biology, and other novel materials including graphene, plasmonic materials, and printable gratings [154][155][156][157][158][159]. In improving the sensitivity and providing a user-friendly interface, bioinspired photonic structures, colloidal crystal arrays, diffraction gratings and holographic sensors can offer newer capabilities and readout approaches [160][161][162][163][164][165].…”

Section: Next Generation Diagnosticsmentioning

confidence: 99%

Point-of-Care Diagnostics

Yetisen

2014

Holographic Sensors

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Rapid tests that are low-cost and portable are the first line of defence in healthcare systems. Dipstick and lateral-flow are the two universal assay formats as they are lightweight and compact, and provide qualitative results without external instrumentation. However, existing formats have limitations in the quantification of analyte concentrations. Hence, the demand for sample preparation, improved sensitivity and user-interface has challenged the commercial products. Recently, capabilities, sensors and readout devices were expanded to multiplexable assays platforms, which might transcend the capabilities of existing design format of diagnostic tests. This chapter outlines the evolution of diagnostic devices and current trends in the development of qualitative and quantitative sensing devices for applications in healthcare, veterinary medicine, environmental monitoring and food safety. The chapter also discusses design parameters for diagnostics, their functionalisation to increase the capabilities and the performance, emerging sensing platforms and readout technologies. The factors which limit the emerging rapid diagnostics to become commercial products are also discussed.The life expectancy has grown worldwide, which also increased the healthcare spending [1, 2]. For example, 720 million people will be aged 65 or older by 2020. Currently four in five people over the age of 75 take at least one prescribed medicine, and this trend is set to increase [3]. For some of the medications, large pharma find it the hard to recover R&D costs while the pressure from the regulatory agencies also increased for the use of new drugs as the first line of defence based on efficacy and cost. Hence, the global healthcare trends and ever increasing pressure from regulatory agencies put a strong case for the development of diagnostics for healthcare monitoring as well as the evaluation of drug efficacies in clinical trials. All these considerations parallels governments' and insurance companies' interests in obtaining the best performance possible and treatment benefits they support. These trends are behind the driving force for the development of diagnostics that can reduce the healthcare costs by developing effective drugs and identifying diseases and conditions at an early stage.The major stumbling block in monitoring and controlling diseases/contaminations remains delivering simple, low-cost and robust diagnostic tests [4,5]. In the developing world, the basic healthcare infrastructure and trained healthcare personnel are

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“…The efficiency remains constant at $0.055%, which is in agreement with the literature. 43 However, the graphene plasmonic lens displays increased focusing efficiency at higher carrier mobilities.…”

Section: Simulation Of Wavelength-selective Enhanced Graphene Lensmentioning

confidence: 99%