Browsing by Subject "Halide perovskites"

Now showing 1 - 3 of 3

Embargo
Giant ultrafast all-optical modulation based on exceptional points in exciton–polariton perovskite metasurfaces
(American Chemical Society, 2024-01-22) Masharin, Mikhail A.; Oskolkova, Tatiana; Işık, Furkan; Demir, Hilmi Volkan; Samusev, A. K.; Makarov, S .V.
Ultrafast all-optical modulation with optically resonant nanostructures is an essential technology for high-speed signal processing on a compact optical chip. Key challenges that exist in this field are relatively low and slow modulations in the visible range as well as the use of expensive materials. Here we develop an ultrafast all-optical modulator based on MAPbBr3 perovskite metasurface supporting exciton–polariton states with exceptional points. The additional angular and spectral filtering of the modulated light transmitted through the designed metasurface allows us to achieve 2500% optical signal modulation with the shortest modulation time of 440 fs at the pump fluence of ∼40 μJ/cm2. Such a value of the modulation depth is record-high among the existing modulators in the visible range, while the main physical effect behind it is polariton condensation. Scalable and cheap metasurface fabrication via nanoimprint lithography along with the simplicity of perovskite synthesis and deposition make the developed approach promising for real-life applications.
Embargo
Nanoimprinted halide perovskite nanowires with directly-written gratings
(Elsevier BV, 2022-12-01) Pushkarev, A.P.; Sinev, I.S.; Ladutenko, K.S.; Song, M.; Demir, Hilmi Volkan; Makarov, S.V.
Perovskite nanowires demonstrate low-threshold lasing owing to the huge optical gain of their material and their self-resonance behavior. However, their lasing properties still can be optimized and improved because light outcoupling through their subwavelength facets is not optimal for many applications. Here we demonstrate a versatile method for improvement of the lasing properties of a single perovskite CsPbBr3 nanowire by defining an additional grating on its surface. Such direct patterning is carried out by high-throughput nanoimprinting method, which does not damage the material or worsen its material properties as it might happen after applying conventional lithographical approaches. Such direct imprinting of gratings on the CsPbBr3 nanowires provides us with the ability to modify their eigen- modes, improve directivity of their outcoupled stimulated emission and narrow their lasing spectral lines, while keeping their lasing threshold almost unchanged. Concurrently, the number of their modes are reduced (by half) and the quality factor of their remaining lasing modes is increased (by about 2-folds). These findings indicate that direct writing of nanopatterns on halide perovskite nanowires via nanoimprint lithography holds great promise for imparting additional structural functions to these nanowires while leaving their material unharmed. © 2022 Elsevier B.V.
Open Access
Observation of enhanced generation of a fifth harmonic from halide perovskite nonlocal metasurfaces
(American Chemical Society, 2023-03-11) Tonkaev, P.; Koshelev, K.; Masharin, Mikhail A.; Makarov, S. V.; Kruk, S. S.; Kivshar, Y.
Lead halide perovskites are widely employed in photonic and light-emitting devices because of their rich optoelectronic properties and simplicity of fabrication based on low-cost flexible technologies. Perovskite bulk crystals and films demonstrate outstanding nonlinear characteristics with large optical nonlinearities exceeding the nonlinear susceptibilities of conventional semiconductor materials by several orders of magnitude. One of the promising approaches for further enhancement of the nonlinear response of perovskites as dielectric photonic materials is to employ optical resonances of structured surfaces, or metasurfaces. Nonlocal metasurfaces supporting lattice modes over many unit cells provide a new approach to both spatial and spectral control of light fields, and they may deliver improved characteristics of nonlinear effects for a wide range of applications associated with broadband excitation of multiple high-quality resonances. Here we report on the first observation of enhanced fifth harmonic generation in MAPbBr3 halide perovskite nonlocal metasurfaces driven by high-quality resonances at the generated harmonic wavelength in the visible frequency range. The demonstrated enhancement is about 2 orders of magnitude compared to an unpatterned MAPbBr3 film of the same thickness, and is broadband by virtue of the excitation of multiple resonant modes in the highly nonlocal regime. Our work suggests a novel approach for achieving parametric processes in resonant dielectric structures with high efficiency.