Ukuvuselelwa kwama-harmonics esibili kububanzi obubanzi
Kusukela ekutholakaleni kwemiphumela yokukhanya engeyona eye-oda lesibili ngawo-1960, kuye kwavusa isithakazelo esikhulu sabacwaningi, kuze kube manje, ngokusekelwe ku-harmonic yesibili, kanye nemiphumela yemvamisa, ikhiqize kusukela ku-ultraviolet extreme kuya ku-far infrared band yeama-laser, kwakhuthaza kakhulu ukuthuthukiswa kwe-laser,ukukhanyaukucutshungulwa kolwazi, izithombe ezincane ezinesinqumo esiphezulu kanye neminye imikhakha. Ngokusho kwe-nonlinearizibuko zokukhanyakanye nethiyori ye-polarization, umphumela we-optical onge-order onge-linear uhlobene kakhulu nokulingana kwekristalu, futhi i-coefficient enge-linear ayiyona i-zero kuphela kwimidiya ye-symmetric enge-central inversion. Njengomphumela oyisisekelo kakhulu we-second-order nonlinear, ama-harmonics esibili ayaphazamisa kakhulu ukukhiqizwa kwawo kanye nokusetshenziswa kwawo okuphumelelayo ku-fiber ye-quartz ngenxa yesimo esingaguquki kanye nokulingana kwe-central inversion. Njengamanje, izindlela ze-polarization (i-optical polarization, i-thermal polarization, i-electric field polarization) zingabhubhisa ngokwenziwa ukulingana kwe-material center inversion ye-fiber ye-optical, futhi zithuthukise ngempumelelo ukungalingani kwe-second-order ye-fiber ye-optical. Kodwa-ke, le ndlela idinga ubuchwepheshe bokulungiselela obuyinkimbinkimbi nobudingayo, futhi ingahlangabezana kuphela nezimo zokufanisa ze-quasi-phase kuma-wavelength ahlukene. Indandatho ye-optical fiber resonant esekelwe kumodi yodonga lwe-echo ikhawulela ukukhushulwa kwe-wide spectrum yama-harmonics esibili. Ngokuphula ukulingana kwesakhiwo sobuso be-fiber, ama-harmonics esibili obuso ku-fiber yesakhiwo esikhethekile ayathuthukiswa ngezinga elithile, kodwa asancike ku-pulse ye-femtosecond pump enamandla aphezulu kakhulu. Ngakho-ke, ukukhiqizwa kwemiphumela ye-optical engeyona eye-oda lesibili ezakhiweni ze-fiber yonke kanye nokuthuthukiswa kokusebenza kahle kokuguqulwa, ikakhulukazi ukukhiqizwa kwe-harmonics yesibili ye-wide-spectrum ekupompeni kwe-optical okuqhubekayo okunamandla aphansi, yizinkinga eziyisisekelo ezidinga ukuxazululwa emkhakheni we-fiber optics namadivayisi angeyona eye-linear, futhi zinokubaluleka okubalulekile kwesayensi kanye nenani lokusetshenziswa elibanzi.
Ithimba locwaningo eShayina liphakamise uhlelo lokuhlanganisa isigaba sekristalu se-gallium selenide esinezingqimba ezine-micro-nano fiber. Ngokusebenzisa i-nonlinearity ephezulu ye-second-order kanye nokuhleleka okude kwamakristalu e-gallium selenide, inqubo yokuvuselela i-second-harmonic ebanzi kanye nenqubo yokuguqula ama-frequency amaningi iyafezeka, okuhlinzeka ngesisombululo esisha sokuthuthukisa izinqubo ze-multi-parametric ku-fiber kanye nokulungiselela i-broadband second-harmonic.imithombo yokukhanya. Ukuvuselelwa okusebenzayo komphumela wesibili we-harmonic kanye ne-sum frequency kuhlelo kuncike kakhulu ezimweni ezintathu ezibalulekile ezilandelayo: ibanga elide lokuxhumana kokukhanya-into phakathi kwe-gallium selenide kanyei-micro-nano fiber, ukungalandeli kwe-second-order ephezulu kanye nokuhleleka okude kwekristalu ye-gallium selenide enezingqimba, kanye nezimo zokufanisa isigaba semodi yokuphindaphindwa kwemvamisa eyisisekelo kanye nemvamisa kuyaneliswa.
Kulolu cwaningo, i-micro-nano fiber elungiselelwe uhlelo lokuskena ilangabi inendawo efanayo yekhoni ngokulandelana kwe-millimeter, enikeza ubude besenzo obude obungelulo umugqa wokukhanya kwephampu kanye negagasi lesibili le-harmonic. I-polarizability ye-second-order nonlinear yekristalu ehlanganisiwe ye-gallium selenide idlula i-170 pm/V, ephakeme kakhulu kune-polarizability yangaphakathi engelulo umugqa we-optical. Ngaphezu kwalokho, isakhiwo esihleliwe se-long-range sekristalu ye-gallium selenide siqinisekisa ukuphazamiseka okuqhubekayo kwe-harmonics yesibili, okunikeza ukudlala okugcwele inzuzo yobude besenzo esikhulu esingelulo umugqa we-micro-nano fiber. Okubaluleke kakhulu, ukufana kwesigaba phakathi kwemodi yesisekelo se-optical pumping (HE11) kanye nemodi yesibili ye-harmonic high order (EH11, HE31) kutholakala ngokulawula ububanzi bekhoni bese kulawulwa ukusabalala kwe-waveguide ngesikhathi sokulungiselela i-micro-nano fiber.
Lezi zimo ezingenhla zibeka isisekelo sokukhushulwa kwe-harmonics yesibili okusebenzayo nokubanzi ku-micro-nano fiber. Ukuhlolwa kukhombisa ukuthi umphumela we-harmonics yesibili ezingeni le-nanowatt ungatholakala ngaphansi kwephampu ye-laser ye-picosecond pulse engu-1550 nm, kanti i-harmonics yesibili nayo ingavuselelwa ngempumelelo ngaphansi kwephampu ye-laser eqhubekayo yobude obufanayo, futhi amandla omkhawulo aphansi njengama-microwatts angamakhulu amaningana (Isithombe 1). Ngaphezu kwalokho, lapho ukukhanya kwephampu kunwetshwa kuma-wavelength amathathu ahlukene e-laser eqhubekayo (1270/1550/1590 nm), ama-harmonics amathathu esibili (2w1, 2w2, 2w3) kanye nezimpawu ezintathu ze-sum frequency (w1+w2, w1+w3, w2+w3) zibonwa ku-wavelength ngayinye yama-wavelengths ayisithupha okuguqulwa kwemvamisa. Ngokushintsha isibani sephampu ngomthombo wokukhanya we-ultra-radiant light-emitting diode (SLED) nge-bandwidth engu-79.3 nm, kukhiqizwa i-harmonic yesibili ye-wide-spectrum ene-bandwidth engu-28.3 nm (Isithombe 2). Ngaphezu kwalokho, uma ubuchwepheshe bokufaka umhwamuko wamakhemikhali bungasetshenziswa ukufaka esikhundleni sobuchwepheshe bokudlulisa okomile kulolu cwaningo, futhi kungatshalwa izingqimba ezimbalwa zamakristalu e-gallium selenide ebusweni be-micro-nano fiber emabangeni amade, ukusebenza kahle kwe-harmonic yesibili kulindeleke ukuthi kuthuthukiswe kakhulu.
ISITHOMBE 1 Uhlelo lwesibili lokukhiqiza i-harmonic kanye nemiphumela yesakhiwo se-fiber yonke
Umfanekiso 2 Ukuxubana kwamagagasi amaningi kanye nama-harmonics esibili e-wide-spectrum ngaphansi kokupompa okuqhubekayo kwe-optical
Isikhathi sokuthunyelwe: Meyi-20-2024