Many new photonic technologies require compact and high-resolution photonic devices, which can manipulate light at sub-wavelength/nanoscale dimensions. At this scale, conventional optical components, such as lenses, are no longer functional, and new approaches and components, such as nanoantennas, should be developed. This has stimulated strong research efforts in the field of nanophotonics, which deals with light properties and manipulation at nanoscale. To date, most of these efforts have been in the scientific domain generating high-impact publications rather than high-impact technologies. Some of the limitations associated with current nanophotonic concepts, especially those based on plasmonic metals, include high losses, incompatibility with traditional CMOS-based fabrication, and high costs of nanofabrication (Science 2016).
Our group is among the pioneers of the new branch of nanophotonics related to nanoantennas based on high-refractive index dielectric and semiconductor materials, which can solve the major problem of losses and is compatible with existing industrial processes. The multipolar resonances supported by these high-index dielectric nanoantennas allow design of systems in which the outcoupled radiation pattern, in particular the directivity, can be tailored at will. Moreover, unlike plasmonic counterparts, local electromagnetic fields in resonant dielectric nanoparticles concentrate inside the structures, rather than outside. This allows enhanced light-matter interactions in the semiconductors that constitute the resonant nanoantennas, thus boosting their linear and nonlinear optical properties. (Proceedings of IEEE 2019).
Our group’s current research is dedicated to active nanoantennas that emit, enhance, and shape light. Over the years, we have demonstrated lasing in various nanoantenna structures and gain media, including lasing in a sub-wavelength single particle (0D) (ACS Nano 2020), a nanochain of particles (1D) (Nano Letters 2020), and nanopillar arrays (2D) (Nature Nanotechnology 2018 & Nano Letters 2020).
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Currently, our research programme, named “Nanoantenna Light-Emitting Devices”, aims to enhance the performance of light-emitting devices, including colour-converting films, light-emitting diodes, and lasers, using optically resonant nanoantennas. Here, we target devices based on colloidal quantum emitters (CQEs), such as solution-processed quantum dots, quantum wells, and upconversion nanoparticles. CQE-based devices enhanced by dielectric nanoantennas can lead to a wide range of applications. For example, efficient downconversion of blue photons into green or red ones could be integrated with microLEDs, making ultra-high-resolution microdisplays possible. On the other hand, efficient upconversion of short-wave infrared (SWIR) photons into higher-energy ones could enable inexpensive silicon-based SWIR detectors with applications across medical, industrial, agricultural, military, and scientific fields. Looking forward, the successful development of CQE-based micro-lasers, with their compatibility on CMOS wafers or flexible, transparent substrates, relative ease and low cost of fabrication, and wide tunability in emission wavelength, will profoundly impact fields such as integrated photonics, communications, information processing, biomedicine, and advanced displays.
In parallel to academic research, we are continually looking to translate these cutting-edge concepts into real-world applications. For that, we actively seek to engage industrial partners to transfer the technologies and principles developed in our group into practical devices.