Anomalous Absorption in Arrays of Metallic Nanoparticles: A Powerful Tool for Quantum Dot Optoelectronics

Abstract

Periodic arrays of noble metal nanoparticles are emblematic nanostructures in photonics. Their ability to sustain localized surface plasmon resonances has been used throughout the years to demonstrate a variety of passive and active functionalities such as enhanced luminescence in dipolar media and LEDs as well as higher responsivities in photoconductive detectors. Here, we show that additional magnetic resonances, associated with inductive current loops between the nanoparticles and accessible with transverse electric waves, emerge in the limit of dense arrays with subwavelength periods. Moreover, their interplay with the plasmons of the system results in spectrally sharp analogs of electromagnetically induced absorption (EIA). We use these metasurfaces to induce changes and enhancements in the emission, absorption, photoconduction and polarization properties of active layers of PbS nanocrystals, illustrating the potential of EIA beyond the passive functionalities demonstrated so far in the literature.

Ultrafast Charge Carrier Dynamics and Transport Characteristics in HgTe Quantum Dots

“…While the field of HgTe quantum dot (QD) colloidal chemistry that started back in the 90s in Horst Weller’s group , is well developed nowadays and has come to provide synthetic recipes for a wide range of QD sizes and thus tunable emission wavelengths up to the mid-infrared (IR) range, − the research focus has shifted more toward IR-device engineering aspects. Various approaches have been implemented to obtain high-performance optoelectronic devices, such as coupling with plasmonic structures, − ligand engineering, surface chemistry control, , a more sophisticated development of the architecture of the device itself, − and so on. During the past 20 years the field of IR optoelectronic devices based on HgX (X = S, Se, Te) colloidal QDs has experienced impressive developments. , Up to date photodetectors with a responsivity up to 10 6 A/W and detectivity of 10 12 Jones beyond 2 μm have been reported. ,, Recently, by combining HgTe QDs and graphene, the sensitivity of phototransistors was greatly improved at wavelengths up to 3 μm .…”

Nanocrystal-Based Active Photonics Device through Spatial Design of Light-Matter Coupling

“…The resulting thin films are thus poorly photoresponsive, and light management strategies have to be introduced to absorb a significant part of the incident light into a NC slab whose size matches the diffusion length. In diodes based on vertical transport, absorption enhancement can be obtained by employing Fabry–Perot (F–P) cavities. , More advanced geometries have been proposed to harness the coupling with light, including plasmonic cavities, − guided mode resonators, − F–P resonators, metal–insulator–metal patches, − metasurfaces, , and combinations of these light resonators. By introducing the resonators, the absorption spectrum of the device can be reshaped with respect to that of the absorbing NCs.…”

“…In diodes based on vertical transport, absorption enhancement can be obtained by employing Fabry−Perot (F−P) cavities. 7,8 More advanced geometries have been proposed to harness the coupling with light, 9 including plasmonic cavities, 10−15 guided mode resonators, 16−19 F−P resonators, 20 metal−insulator− metal patches, 21−23 metasurfaces, 24,25 and combinations of these light resonators. By introducing the resonators, the absorption spectrum of the device can be reshaped with respect to that of the absorbing NCs.…”

Helmholtz Resonator Applied to Nanocrystal-Based Infrared Sensing

“…This has raised the need to couple the absorbing/emitting layer to a photonic structure 12 to shape the absorption 13 or enhance its magnitude. 14−16 Several concepts of photonic structures have been explored, including surface plasmonics, 17 a metal−insulator−metal cavity, 18 optical lens, 19 Fabry−Perot cavity, 20 plasmonic cavity, 21,22 guided-mode resonator, 23−25 epsilon-near-zero resonator, 26,27 electromagnetically induced absorber, 28 distributed Bragg reflector 13,29 and even the combination of some of them. 14,30 In this paper, we explore the design of an optical resonator equivalent to a Helmholtz resonator initially developed for acoustics, 31 see Figure 1a.…”

“…However, in most devices, the light-matter interaction is dictated by the electronic structure of the material itself. This has raised the need to couple the absorbing/emitting layer to a photonic structure to shape the absorption or enhance its magnitude. − Several concepts of photonic structures have been explored, including surface plasmonics, a metal–insulator–metal cavity, optical lens, Fabry−Perot cavity, plasmonic cavity, , guided-mode resonator, − epsilon-near-zero resonator, , electromagnetically induced absorber, distributed Bragg reflector , and even the combination of some of them. , …”