Ukuhambela phambili kwi-ultraviolet ngokugqithiseleyoiteknoloji yomthombo wokukhanya
Kwiminyaka yakutshanje, imithombo egqithisileyo ye-ultraviolet ephezulu ye-harmonic iye yatsala ingqalelo ebanzi kwintsimi ye-electron dynamics ngenxa yokubambisana okuqinileyo, ixesha elifutshane le-pulse kunye namandla aphezulu e-photon, kwaye isetyenziswe kwizifundo ezahlukeneyo ze-spectral kunye ne-imaging. Ngokuhambela phambili kwetekhnoloji, okuumthombo wokukhanyaiphuhlisa isiya kuphindaphindwa rhoqo, i-photon flux ephezulu, amandla aphezulu efoton kunye nobubanzi obufutshane bepulse. Oku kuqhubela phambili akwanelisi kuphela ukusonjululwa komlinganiselo wemithombo yokukhanya ye-ultraviolet egqithisileyo, kodwa ikwabonelela ngamathuba amatsha kwiindlela zophuhliso lwetekhnoloji kwixesha elizayo. Ke ngoko, uphononongo olunzulu kunye nokuqonda okuphindaphindwayo okuphindaphindiweyo komthombo wokukhanya kwe-ultraviolet kubaluleke kakhulu ekulawuleni nasekusebenziseni itekhnoloji yokusika.
Kwimilinganiselo ye-electron spectroscopy kwi-femtosecond kunye ne-attosecond time scales, inani leziganeko ezilinganiswa kumqadi omnye lihlala lingonelanga, okwenza imithombo yokukhanya ephindaphindwayo ephantsi ingonelanga ukufumana izibalo ezithembekileyo. Ngelo xesha, umthombo wokukhanya kunye ne-photon flux ephantsi iya kunciphisa i-signal-to-noise ratio ye-imaging microscopic ngexesha lokuvezwa okulinganiselweyo. Ngophononongo oluqhubekayo kunye novavanyo, abaphandi baye benza uphuculo oluninzi ekuphuculeni isivuno kunye noyilo lokuhambisa ukuphindaphinda okuphindaphindiweyo kokukhanya okugqithisileyo kwe-ultraviolet. Itekhnoloji yohlalutyo oluphezulu lwe-spectral edityaniswe nokuphindaphinda okuphindaphindiweyo komthombo wokukhanya kwe-ultraviolet isetyenziselwe ukufezekisa umlinganiselo ophezulu wokuchaneka kwesakhiwo sezinto kunye nenkqubo ye-electronic dynamic.
Ukusetyenziswa kwemithombo yokukhanya ye-ultraviolet egqithisileyo, efana nemilinganiselo ye-electron spectroscopy (ARPES) esonjululweyo, ifuna umtha wokukhanya okugqithisileyo kwe-ultraviolet ukukhanyisa isampuli. I-electron phezu kwesampulu iyavuya kwimeko eqhubekayo ngokukhanya okukhulu kwe-ultraviolet, kwaye amandla e-kinetic kunye ne-emission Angle ye-photoelectrons iqulethe ulwazi lwesakhiwo sebhendi yesampuli. I-electron analyzer enomsebenzi we-Angle isisombululo ifumana ii-photoelectrons ezisasazwayo kwaye ifumana isakhiwo sebhendi kufuphi nebhendi ye-valence yesampuli. Ukuphindaphinda okuphantsi komthombo wokukhanya okugqithisileyo kwe-ultraviolet, ngenxa yokuba i-pulse yayo iqulethe inani elikhulu leefotoni, iya kuvuyisa inani elikhulu lee-photoelectrons kumphezulu wesampulu ngexesha elifutshane, kwaye intsebenziswano ye-Coulomb iya kuzisa ukwanda okukhulu kokusasazwa kwamandla e-photoelectron kinetic, ebizwa ngokuba yi-space charge effect. Ukuze kuncitshiswe impembelelo yesiphumo sentlawulo yendawo, kuyimfuneko ukunciphisa ii-photoelectrons eziqulethwe kwi-pulse nganye ngelixa ugcina i-photon flux rhoqo, ngoko kuyimfuneko ukuqhubalaserngokuphindaphinda okuphindaphindiweyo ukuvelisa umthombo wokukhanya ogqithiseleyo we-ultraviolet kunye nokuphindaphinda okuphindaphindiweyo.
Itekhnoloji ye-resonance eyandisiweyo ye-cavity iqonda ukuveliswa kwee-harmonics ezikumgangatho ophezulu kuphindaphindo lwe-MHz
Ukuze ufumane umthombo wokukhanya ogqithiseleyo we-ultraviolet kunye nezinga lokuphindaphinda ukuya kwi-60 MHz, iqela likaJones kwiYunivesithi yaseBritish Columbia e-United Kingdom lenze isizukulwana esiphezulu se-harmonic kwi-femtosecond resonance enhancement cavity (fsEC) ukufezekisa umthombo wokukhanya ogqithiseleyo we-ultraviolet kwaye uyisebenzise kwi-experiment ye-angular esonjululwe i-electron spectroscopy (TRPES) Umthombo wokukhanya unako ukuhambisa i-photon flux engaphezulu kweenombolo ze-photon ze-1011 ngesibini kunye ne-harmonic enye kwizinga lokuphindaphinda kwe-60 MHz kuluhlu lwamandla lwe-8 ukuya kwi-40 eV. Basebenzise inkqubo ye-fiber laser ye-ytterbium-doped njengomthombo wembewu ye-fsEC, kunye neempawu ze-pulse ezilawulwayo ngoyilo lwenkqubo ye-laser eyenziwe ngokwezifiso ukunciphisa ingxolo yomthwali we-envelope offset frequency (fCEO) kunye nokugcina iimpawu ezintle zoxinzelelo lwe-pulse ekupheleni kwekhonkco le-amplifier. Ukufezekisa ukuphuculwa okuzinzile kwe-resonance ngaphakathi kwe-fsEC, basebenzisa i-loops yokulawula i-servo emithathu yokulawula impendulo, okubangelwa ukuzinza okusebenzayo kwiidigri ezimbini zenkululeko: ixesha lokujikeleza lokujikeleza kwe-pulse cycling ngaphakathi kwe-fsEC ihambelana nexesha le-laser pulse, kunye nokutshintshwa kwesigaba somthwali wentsimi yombane ngokubhekiselele kwimvulophu ye-pulse (oko kukuthi, isigaba se-envelope ϕCEO).
Ngokusebenzisa igesi ye-krypton njengegesi esebenzayo, iqela lophando liphumelele ukuveliswa kwee-harmonics eziphezulu kwi-fsEC. Benza imilinganiselo ye-Tr-ARPES yegraphite kwaye baqaphela ukufudumeza okukhawulezileyo kunye nokuhlanganiswa okucothayo okulandelayo kwe-electron yabantu abangenayo i-thermally enomdla, kunye neentshukumo zamazwe angenamdla ngokuthe ngqo kufuphi nenqanaba leFermi ngaphezu kwe-0.6 eV. Lo mthombo wokukhanya unika isixhobo esibalulekileyo sokufunda isakhiwo sombane sezinto eziyinkimbinkimbi. Nangona kunjalo, ukuveliswa kwee-harmonics zomyalelo ophezulu kwi-fsEC kuneemfuno eziphezulu kakhulu zokubonakala, imbuyekezo ye-dispersion, ukulungiswa kakuhle kobude be-cavity kunye nokutshixa ungqamaniso, okuya kuchaphazela kakhulu ukuphuculwa kokuphindaphinda kwe-resonance-enhanced cavity. Ngexesha elifanayo, impendulo yesigaba esingenasiphelo seplasma kwindawo egxininisekileyo yecavity nayo ingumngeni. Ngoko ke, okwangoku, olu hlobo lomthombo wokukhanya aluzange lube yinto eqhelekileyo ye-ultravioletumthombo wokukhanya ophezulu we-harmonic.
Ixesha lokuposa: Apr-29-2024