Bandi yolumikizirana ya kuwala, resonator yopyapyala kwambiri ya kuwala

Bandi yolumikizirana ya kuwala, resonator yopyapyala kwambiri ya kuwala
Ma resonator optical amatha kupeza mafunde enaake a mafunde a kuwala pamalo ochepa, ndipo amakhala ndi ntchito zofunika kwambiri pakulumikizana kwa kuwala ndi zinthu zina,kulankhulana kwa kuwala, kuzindikira kwa kuwala, ndi kuphatikiza kwa kuwala. Kukula kwa resonator kumadalira makamaka mawonekedwe a zinthu ndi kutalika kwa nthawi yogwirira ntchito, mwachitsanzo, ma resonator a silicon omwe amagwira ntchito mu gulu la infrared lomwe lili pafupi nthawi zambiri amafunikira mapangidwe a kuwala a ma nanometer mazana ambiri kapena kupitirira apo. M'zaka zaposachedwa, ma resonator opepuka kwambiri a planar akhala akukopa chidwi chachikulu chifukwa cha momwe angagwiritsire ntchito mu utoto wa kapangidwe kake, kujambula kwa holographic, malamulo a kuwala ndi zida zamagetsi. Momwe mungachepetsere makulidwe a ma resonator a planar ndi limodzi mwa mavuto ovuta omwe ofufuza amakumana nawo.
Mosiyana ndi zipangizo zachikhalidwe za semiconductor, zotchingira za 3D topological (monga bismuth telluride, antimony telluride, bismuth selenide, ndi zina zotero) ndi zipangizo zatsopano zodziwitsira zomwe zili ndi topologically protected metal surface states ndi insulator states. Mkhalidwe wa pamwamba umatetezedwa ndi nthawi yosinthasintha, ndipo ma electron ake samwazikana ndi zonyansa zopanda maginito, zomwe zimakhala ndi mwayi wofunikira wogwiritsidwa ntchito mu quantum computing ndi zipangizo za spintronic zochepa. Nthawi yomweyo, zipangizo zotchingira za topological zimasonyezanso mawonekedwe abwino kwambiri, monga high refractive index, large nonlinear.kuwalacoefficient, wide working spectrum range, tuningability, easy integration, etc., zomwe zimapereka nsanja yatsopano yokwaniritsira malamulo a kuwala ndizipangizo zamagetsi za optoelectronic.
Gulu lofufuza ku China lapereka njira yopangira ma resonator owonda kwambiri pogwiritsa ntchito ma nanofilms a bismuth telluride topological insulator. Mphepete mwa kuwala ikuwonetsa mawonekedwe omveka bwino a resonance absorption mu band yapafupi ndi infrared. Bismuth telluride ili ndi refractive index yoposa 6 mu band yolumikizirana ya optical (yokwera kuposa refractive index ya zipangizo zamakono za refractive index monga silicon ndi germanium), kotero kuti makulidwe a optical cavity amatha kufika pa 1-20th ya resonance wavelength. Nthawi yomweyo, optical resonator imayikidwa pa crystal ya photonic imodzi-dimensional, ndipo mphamvu yatsopano yowonekera yomwe imachitika chifukwa cha electromagnetically imawonekera mu optical communication band, yomwe imachitika chifukwa cha kulumikizana kwa resonator ndi Tamm plasmon ndi kusokoneza kwake kowononga. Yankho la spectral la izi limadalira makulidwe a optical resonator ndipo ndi lolimba pakusintha kwa ambient refractive index. Ntchitoyi imatsegula njira yatsopano yokwaniritsira ultrathin optical cavity, topological insulator material spectrum regulation ndi optoelectronic devices.
Monga momwe zasonyezedwera pa Chithunzi 1a ndi 1b, resonator ya optical imapangidwa makamaka ndi bismuth telluride topological insulator ndi silver nanofilms. Ma bismuth telluride nanofilms okonzedwa ndi magnetron sputtering ali ndi malo akuluakulu komanso osalala bwino. Pamene makulidwe a bismuth telluride ndi mafilimu asiliva ali 42 nm ndi 30 nm, motsatana, optical cavity imawonetsa kuyamwa kwamphamvu kwa resonance mu band ya 1100 ~ 1800 nm (Chithunzi 1c). Ofufuzawo ataphatikiza optical cavity iyi pa crystal ya photonic yopangidwa ndi zigawo zosinthika za Ta2O5 (182 nm) ndi SiO2 (260 nm) (Chithunzi 1e), chigwa chodziwika bwino cha kuyamwa (Chithunzi 1f) chinawonekera pafupi ndi resonant absorption peak yoyambirira (~1550 nm), yomwe ili yofanana ndi electromagnetically induced transparency effect yopangidwa ndi ma atomu systems.

Zinthu za bismuth telluride zinkadziwika ndi ma microscopy a ma electron otumizira ndi ellipsometry. Chithunzi 2a-2c chikuwonetsa ma micrograph a ma electron otumizira (zithunzi zapamwamba) ndi mapangidwe osankhidwa a ma electron diffraction a ma nanofilms a bismuth telluride. Zitha kuwoneka kuchokera pachithunzichi kuti ma nanofilms a bismuth telluride okonzedwa ndi zinthu za polycrystalline, ndipo kukula kwakukulu ndi (015) crystal plane. Chithunzi 2d-2f chikuwonetsa index yovuta ya refractive ya bismuth telluride yoyesedwa ndi ellipsometer ndi index yokhazikika ya pamwamba ndi state complex refractive. Zotsatira zake zikuwonetsa kuti coefficient ya extinction ya surface state ndi yayikulu kuposa index ya refractive yomwe ili pakati pa 230 ~ 1930 nm, kuwonetsa mawonekedwe ofanana ndi chitsulo. Chizindikiro cha refractive cha thupi chimaposa 6 pamene kutalika kwa mafunde kuli koposa 1385 nm, komwe kuli kokwera kwambiri kuposa kwa silicon, germanium ndi zida zina zachikhalidwe zapamwamba zowunikira mu gulu ili, zomwe zimayika maziko okonzekera ma resonators owonda kwambiri. Ofufuzawo akunena kuti uku ndi koyamba kunenedwa kwa chotchinga chowongolera cha topological chokhala ndi makulidwe a ma nanometer makumi okha mu gulu lolumikizirana la optical. Pambuyo pake, ma absorption spectrum ndi ma resonance wavelength a ultra-thin optical cavity adayesedwa ndi makulidwe a bismuth telluride. Pomaliza, zotsatira za makulidwe a siliva pa ma spectra owonekera omwe amapangidwa ndi electromagnetically mu bismuth telluride nanocavity/photonic crystal structures zafufuzidwa.

Mwa kukonza mafilimu opyapyala a bismuth telluride topological insulators okhala ndi malo akuluakulu, ndikugwiritsa ntchito chizindikiro cha refractive cha zinthu za Bismuth telluride mu near infrared band, pamapezeka planar optical cavity yokhala ndi makulidwe a makumi a nanometers okha. Ultra-thin optical cavity imatha kuyamwa bwino kuwala kwa resonant mu near infrared band, ndipo ili ndi phindu lofunika pakupanga zida zamagetsi mu optical communication band. Kukhuthala kwa bismuth telluride optical cavity ndi kolunjika ku resonant wavelength, ndipo ndi kochepa kuposa kwa silicon ndi germanium optical cavity yofanana. Nthawi yomweyo, bismuth telluride optical cavity imalumikizidwa ndi photonic crystal kuti ikwaniritse zotsatira zachilendo za optical zofanana ndi electromagnetically induced clearance ya atomic system, zomwe zimapereka njira yatsopano yowongolera ma microstructure. Kafukufukuyu ali ndi gawo linalake polimbikitsa kafukufuku wa zinthu za topological insulator mu regulation of light and optical functional devices.