Laser ya TW class attosecond X-ray pulse

Laser ya TW class attosecond X-ray pulse
X-ray ya Attosecondlaser ya kugunda kwa mtimaPogwiritsa ntchito mphamvu zambiri komanso nthawi yochepa yogunda, ndikofunika kwambiri kuti tipeze ma spectroscopy ofulumira kwambiri komanso zithunzi za X-ray diffraction. Gulu lofufuza ku United States linagwiritsa ntchito njira yosiyana siyana.Ma laser a ma elekitironi opanda ma X-raykutulutsa ma pulse a attosecond osiyana. Poyerekeza ndi malipoti omwe alipo, mphamvu yapakati ya ma pulse imawonjezeka ndi kukula kwakukulu, mphamvu yayikulu ya pamwamba ndi 1.1 TW, ndipo mphamvu yapakati ndi yoposa 100 μJ. Kafukufukuyu akuperekanso umboni wamphamvu wa khalidwe la soliton-like superradiation m'munda wa X-ray.Ma laser amphamvu kwambirizatsogolera madera ambiri atsopano ofufuza, kuphatikizapo fizikisi yapamwamba, attosecond spectroscopy, ndi laser particle accelerators. Pakati pa mitundu yonse ya ma laser, ma X-ray amagwiritsidwa ntchito kwambiri pozindikira matenda, kuzindikira zolakwika zamafakitale, kuyang'anira chitetezo ndi kafukufuku wasayansi. X-ray free-electron laser (XFEL) imatha kuwonjezera mphamvu ya X-ray yapamwamba kwambiri ndi ma order angapo poyerekeza ndi ukadaulo wina wopanga ma X-ray, motero kuwonjezera kugwiritsa ntchito ma X-ray kumunda wa nonlinear spectroscopy ndi single-particle diffraction imaging komwe kumafunika mphamvu yayikulu. Attosecond XFEL yopambana posachedwapa ndi kupambana kwakukulu mu sayansi ndi ukadaulo wa attosecond, kuonjezera mphamvu ya peak yomwe ilipo ndi ma order oposa asanu ndi limodzi poyerekeza ndi magwero a X-ray okhala ndi benchtop.

Ma laser a ma elekitironi aulereakhoza kupeza mphamvu za pulse zomwe zili pamwamba kwambiri kuposa mlingo wa kutulutsa kwadzidzidzi pogwiritsa ntchito kusakhazikika kwa gulu, komwe kumachitika chifukwa cha kuyanjana kosalekeza kwa mphamvu ya radiation mu relativistic electron beam ndi magnetic oscillator. Mu X-ray yolimba (pafupifupi 0.01 nm mpaka 0.1 nm wavelength), FEL imapezedwa ndi njira zochepetsera ma bundle ndi post-saturation coning. Mu X-ray yofewa (pafupifupi 0.1 nm mpaka 10 nm wavelength), FEL imayendetsedwa ndi ukadaulo wa cascade fresh-slice. Posachedwapa, ma attosecond pulses okhala ndi mphamvu yayikulu ya 100 GW anenedwa kuti amapangidwa pogwiritsa ntchito njira ya enhanced self-amplified spontaneous emission (ESASE).

Gulu lofufuza linagwiritsa ntchito njira yokwezera mafunde ya magawo awiri pogwiritsa ntchito XFEL kuti iwonjezere mphamvu ya kugunda kwa mtima ya X-ray kuchokera ku linac coherent.gwero la kuwalaku mulingo wa TW, dongosolo la kusintha kwakukulu poyerekeza ndi zotsatira zomwe zanenedwa. Kukhazikitsa kwa kuyesera kwawonetsedwa mu Chithunzi 1. Kutengera njira ya ESASE, chotulutsira cha photocathode chimasinthidwa kuti chipeze kuwala kwa electron komwe kumakhala ndi spike yayikulu, ndipo chimagwiritsidwa ntchito kupanga ma pulse a attosecond X-ray. Kugunda koyambirira kumakhala m'mphepete mwa spike ya kuwala kwa electron, monga momwe zasonyezedwera pakona yakumanzere yakumtunda kwa Chithunzi 1. Pamene XFEL yafika pakukwanira, kuwala kwa electron kumachedwa poyerekeza ndi X-ray ndi compressor yamaginito, kenako pulse imalumikizana ndi kuwala kwa electron (slice yatsopano) komwe sikusinthidwa ndi ESESE modulation kapena FEL laser. Pomaliza, undulator yachiwiri yamaginito imagwiritsidwa ntchito kukulitsa ma X-ray kudzera mu kulumikizana kwa ma attosecond pulses ndi kagawo katsopano.

Chithunzi 1 Chithunzi cha chipangizo choyesera; Chithunzichi chikuwonetsa malo a gawo longitudinal (chithunzi cha nthawi-mphamvu cha elekitironi, chobiriwira), mawonekedwe apano (buluu), ndi kuwala komwe kumapangidwa ndi kukulitsa kwa dongosolo loyamba (wofiirira). XTCAV, X-band transverse cavity; cVMI, coaxial rapid mapping system; FZP, Fresnel band plate spectrometer

Ma pulse onse a attosecond amapangidwa kuchokera ku phokoso, kotero pulse iliyonse ili ndi mawonekedwe osiyana a spectral ndi nthawi-domain, zomwe ofufuza adafufuza mwatsatanetsatane. Ponena za ma spectra, adagwiritsa ntchito Fresnel band plate spectrometer kuti ayesere ma spectra a ma pulse osiyanasiyana pa utali wofanana wa undulator, ndipo adapeza kuti ma spectra awa adasunga ma waveform osalala ngakhale atatha kukulitsa kwachiwiri, zomwe zikusonyeza kuti ma pulses adakhalabe amodzi. Mu nthawi, fringe ya angular imayesedwa ndipo mawonekedwe a nthawi ya pulse amafotokozedwa. Monga momwe zasonyezedwera pa Chithunzi 1, pulse ya X-ray imalumikizidwa ndi pulse ya infrared laser yozungulira. Ma photoelectron omwe amapangidwa ndi X-ray pulse amapanga mizere yosiyana ndi mphamvu ya vector ya laser ya infrared. Chifukwa mphamvu yamagetsi ya laser imazungulira ndi nthawi, kugawa kwa mphamvu ya photoelectron kumatsimikiziridwa ndi nthawi yotulutsa ma electron, ndipo ubale pakati pa njira ya angular ya nthawi yotulutsa ndi kugawa kwa mphamvu ya photoelectron umakhazikitsidwa. Kugawa kwa mphamvu ya photoelectron kumayesedwa pogwiritsa ntchito spectrometer yojambula zithunzi mwachangu ya coaxial. Kutengera ndi zotsatira za kugawa ndi spectral, mawonekedwe a nthawi ya mafunde a attosecond pulses amatha kumangidwanso. Chithunzi 2 (a) chikuwonetsa kugawa kwa nthawi ya pulse, ndi apakati a 440 as. Pomaliza, chowunikira mpweya chinagwiritsidwa ntchito poyesa mphamvu ya pulse, ndipo scatter plot pakati pa mphamvu ya peak pulse ndi nthawi ya pulse monga momwe zasonyezedwera mu Chithunzi 2 (b) idawerengedwa. Ma configurations atatuwa akugwirizana ndi ma electron beam focusing conditions osiyanasiyana, ma waver coning conditions ndi ma magnetic compressor delay conditions. Ma configurations atatuwa adapereka mphamvu yapakati ya pulse ya 150, 200, ndi 260 µJ, motsatana, ndi mphamvu yayikulu ya peak ya 1.1 TW.

Chithunzi 2. (a) Histogram yogawa ya kutalika kwa theka (Full width (FWHM) pulse length); (b) Scatter plot yofanana ndi mphamvu ya pachimake ndi nthawi ya pulse

Kuphatikiza apo, kafukufukuyu adawonanso koyamba chochitika cha soliton-like superemission mu X-ray band, chomwe chimawoneka ngati kufupika kosalekeza kwa pulse panthawi ya amplification. Chimachitika chifukwa cha kuyanjana kwamphamvu pakati pa ma elekitironi ndi radiation, pomwe mphamvu imasamutsidwa mwachangu kuchokera ku elekitironi kupita kumutu wa X-ray pulse ndikubwerera ku elekitironi kuchokera kumchira wa pulse. Kudzera mu kafukufuku wozama wa chodabwitsa ichi, zikuyembekezeredwa kuti ma X-ray pulses okhala ndi nthawi yochepa komanso mphamvu yayikulu amatha kuchitika powonjezera njira yowonjezera ya superradiation ndikugwiritsa ntchito mwayi wa pulse shortening mu soliton-like mode.