Kev txhawb nqa ntawm qhov thib ob harmonics hauv qhov dav spectrum

Kev txhawb nqa ntawm qhov thib ob harmonics hauv qhov dav spectrum

Txij li thaum nrhiav pom cov teebmeem kho qhov muag thib ob uas tsis yog linear hauv xyoo 1960, tau ua rau cov kws tshawb fawb xav paub ntau, txog tam sim no, raws li qhov teebmeem harmonic thib ob, thiab zaus, tau tsim los ntawm qhov ultraviolet heev mus rau qhov deb infrared band ntawmcov lasers, txhawb nqa kev loj hlob ntawm laser,kho qhov muagkev ua cov ntaub ntawv, kev tshuaj ntsuam xyuas microscopic siab thiab lwm yam teb. Raws li nonlinearkev kho qhov muagthiab kev tshawb fawb polarization, qhov cuam tshuam ntawm qhov tsis sib xws ntawm cov teeb pom kev zoo sib xws yog ze rau kev sib xws ntawm cov siv lead ua ke, thiab cov coefficient nonlinear tsis yog xoom tsuas yog hauv cov xov xwm tsis sib xws ntawm qhov tsis yog-nruab nrab. Raws li qhov yooj yim tshaj plaws thib ob-txheej txheem nonlinear, qhov thib ob harmonics cuam tshuam loj heev rau lawv txoj kev tsim thiab kev siv zoo hauv quartz fiber vim yog daim ntawv amorphous thiab qhov sib xws ntawm qhov chaw inversion. Tam sim no, cov txheej txheem polarization (optical polarization, thermal polarization, hluav taws xob teb polarization) tuaj yeem ua rau puas tsuaj qhov sib xws ntawm cov khoom siv qhov chaw inversion ntawm optical fiber, thiab ua kom zoo dua qhov thib ob-txheej txheem nonlinearity ntawm optical fiber. Txawm li cas los xij, txoj kev no xav tau cov thev naus laus zis npaj ua haujlwm nyuaj thiab xav tau, thiab tsuas yog tuaj yeem ua tau raws li cov xwm txheej sib phim quasi-theem ntawm cov wavelengths sib cais. Lub nplhaib resonant fiber resonant raws li hom phab ntsa echo txwv qhov dav spectrum excitation ntawm qhov thib ob harmonics. Los ntawm kev rhuav tshem qhov sib xws ntawm cov qauv nto ntawm cov fiber, qhov thib ob harmonics hauv cov qauv tshwj xeeb fiber tau txhim kho rau qee qhov, tab sis tseem nyob ntawm lub twj tso kua mis femtosecond nrog lub zog siab heev. Yog li ntawd, kev tsim cov teebmeem kho qhov muag thib ob uas tsis yog linear hauv txhua cov qauv fiber thiab kev txhim kho ntawm kev hloov pauv zoo, tshwj xeeb tshaj yog kev tsim cov harmonics dav dav hauv lub zog qis, kev siv twj tso kua mis optical tas mus li, yog cov teeb meem yooj yim uas yuav tsum tau daws hauv kev ua haujlwm ntawm cov khoom siv fiber nonlinear thiab cov khoom siv, thiab muaj qhov tseem ceeb ntawm kev tshawb fawb thiab tus nqi siv dav.

Ib pab pawg tshawb fawb hauv Suav teb tau tawm tswv yim txog kev sib koom ua ke ntawm cov txheej txheem siv lead ua ke nrog cov micro-nano fiber. Los ntawm kev siv qhov siab thib ob nonlinearity thiab kev txiav txim siab ntev ntawm cov gallium selenide crystals, kev ua kom muaj kev sib raug zoo thib ob thiab ntau zaus tau pom tseeb, muab kev daws teeb meem tshiab rau kev txhim kho cov txheej txheem ntau yam hauv fiber thiab kev npaj ntawm broadband thib ob-harmonic.cov chaw teeb pom kev zooQhov kev ua kom zoo ntawm qhov thib ob harmonic thiab sum frequency effect hauv txoj kev npaj feem ntau nyob ntawm peb qhov tseem ceeb hauv qab no: qhov ntev ntawm lub teeb-matter interaction nrug ntawm gallium selenide thiabmicro-nano fiber, qhov siab thib ob-txheej txheem nonlinearity thiab ntev-ntev kev txiav txim ntawm cov txheej txheem gallium selenide siv lead ua ke, thiab cov xwm txheej sib phim theem ntawm qhov zaus tseem ceeb thiab hom zaus ob npaug tau txaus siab.

Hauv kev sim, cov micro-nano fiber uas tau npaj los ntawm lub tshuab ntsuas nplaim taws muaj ib cheeb tsam cone sib xws hauv qhov kev txiav txim ntawm millimeter, uas muab qhov ntev nonlinear action ntev rau lub teeb twj tso kua mis thiab nthwv dej harmonic thib ob. Qhov thib ob-kev txiav txim nonlinear polarizability ntawm cov gallium selenide siv lead ua ke tshaj 170 pm / V, uas yog siab dua li qhov intrinsic nonlinear polarizability ntawm cov fiber optical. Ntxiv mus, qhov ntev-ntev ordered qauv ntawm cov gallium selenide siv lead ua kom muaj kev cuam tshuam theem txuas ntxiv ntawm cov harmonics thib ob, muab kev ua si tag nrho rau qhov zoo ntawm qhov loj nonlinear action ntev hauv micro-nano fiber. Qhov tseem ceeb tshaj, qhov sib phim theem ntawm hom pumping optical base (HE11) thiab thib ob harmonic high order hom (EH11, HE31) yog paub los ntawm kev tswj lub cone diameter thiab tom qab ntawd tswj cov waveguide dispersion thaum lub sijhawm npaj ntawm micro-nano fiber.

Cov xwm txheej saum toj no yog lub hauv paus rau kev ua kom zoo thiab dav dav ntawm cov harmonics thib ob hauv micro-nano fiber. Qhov kev sim qhia tau hais tias cov zis ntawm cov harmonics thib ob ntawm qib nanowatt tuaj yeem ua tiav hauv qab 1550 nm picosecond pulse laser twj tso kua mis, thiab cov harmonics thib ob kuj tuaj yeem ua kom zoo nyob rau hauv lub twj tso kua mis laser txuas ntxiv ntawm tib lub wavelength, thiab lub zog threshold yog qis li ntau pua microwatts (Daim Duab 1). Ntxiv mus, thaum lub teeb twj tso kua mis txuas ntxiv mus rau peb lub wavelengths sib txawv ntawm cov laser txuas ntxiv (1270/1550/1590 nm), peb lub harmonics thib ob (2w1, 2w2, 2w3) thiab peb lub teeb liab zaus sib sau ua ke (w1 + w2, w1 + w3, w2 + w3) raug pom ntawm txhua qhov ntawm rau lub wavelengths hloov pauv zaus. Los ntawm kev hloov lub teeb twj tso kua mis nrog lub teeb ci ultra-radiant light-emitting diode (SLED) nrog bandwidth ntawm 79.3 nm, lub harmonic thib ob dav dav nrog bandwidth ntawm 28.3 nm yog tsim (Daim Duab 2). Tsis tas li ntawd, yog tias cov thev naus laus zis tso pa tshuaj lom neeg tuaj yeem siv los hloov cov thev naus laus zis hloov pauv qhuav hauv kev tshawb fawb no, thiab tsawg dua cov khaubncaws sab nraud povtseg ntawm gallium selenide crystals tuaj yeem loj hlob ntawm qhov chaw ntawm micro-nano fiber dhau qhov deb ntev, qhov kev hloov pauv harmonic thib ob yuav tsum tau txhim kho ntxiv.

DUAB 1 Lub kaw lus tsim harmonic thib ob thiab cov txiaj ntsig hauv cov qauv fiber tag nrho

Daim Duab 2 Kev sib xyaw ua ke ntawm ntau lub wavelength thiab dav-spectrum thib ob harmonics nyob rau hauv kev siv twj tso kua mis tas mus li