Kufambira mberi mune yakanyanyisa ultravioletlight source tekinoroji
Mumakore achangopfuura, yakanyanyisa ultraviolet yakakwira harmonic masosi yakakwezva kutarisisa kwakakura mumunda wemagetsi emagetsi nekuda kwekubatana kwavo kwakasimba, pfupi pulse duration uye yakakwirira photon simba, uye yakashandiswa mune akasiyana spectral uye imaging zvidzidzo. Nekufambira mberi kwetekinoroji, izvilight sourceiri kusimukira yakanangana nepamusoro pekudzokorora frequency, yakakwira photon flux, yakakwira photon simba uye pfupi pulse hupamhi. Kufambira mberi uku hakungokwidziri chete kuyerwa kwekuyerwa kweakanyanya ultraviolet mwenje masosi, asi zvakare inopa mikana mitsva yeramangwana tekinoroji budiriro mafambiro. Naizvozvo, kudzidza kwakadzama uye kunzwisiswa kweakanyanya kudzokorora frequency yakanyanyisa ultraviolet mwenje sosi yakakosha zvikuru pakubata uye kushandisa yekucheka-kumucheto tekinoroji.
Pazviyero zveelectron spectroscopy pazvikero zvefemtosecond uye attosecond nguva, nhamba yezviitiko zvakayerwa nedanda rimwe chete kazhinji haina kukwana, zvichiita kuti chiedza cherefiquency chisakwane kuwana nhamba dzakavimbika. Panguva imwecheteyo, chitubu chechiedza chine low photon flux chichaderedza chiratidzo-ku-ruzha chiyero che microscopic imaging panguva shoma yekuratidzwa nguva. Kuburikidza nekuenderera mberi kwekuongorora uye zviedzo, vaongorori vakaita kuvandudzwa kwakawanda mukugadzirisa goho uye dhizaini yekutapurirana kwepamusoro kudzokorora frequency yakanyanyisa ultraviolet mwenje. Iyo yepamusoro spectral yekuongorora tekinoroji yakasanganiswa neiyo yakakwirira yekudzokorora frequency yakanyanyisa ultraviolet mwenje sosi yakashandiswa kuwana yakanyanya kuyera kuyerwa kwechimiro chemidziyo uye yemagetsi dynamic process.
Mashandisirwo ezvakanyanya ultraviolet mwenje masosi, senge angular yakagadziriswa electron spectroscopy (ARPES) zviyero, zvinoda danda rekunyanyisa ultraviolet mwenje kuvhenekera sampuli. Maerekitironi ari pamusoro pesample anofara kune inoenderera nyika neyakanyanya ultraviolet mwenje, uye kinetic simba uye emission Angle yemafotoelectrons ane ruzivo rwebhandi chimiro chemuenzaniso. Erekitironi analyzer ine Angle resolution function inogamuchira maphotoelectrons anopenya uye inowana chimiro chebhendi pedyo nebhendi revalence remuenzaniso. Kune yakaderera kudzokorora frequency yakanyanyisa ultraviolet mwenje sosi, nekuti kupuruzira kwayo kuine huwandu hukuru hwemafotoni, ichafadza huwandu hukuru hwemafotoelectrons pamuenzaniso wepamusoro munguva pfupi, uye kupindirana kweCoulomb kuchaunza kuwedzera kwakakomba kwekugovera. ye photoelectron kinetic simba, iyo inonzi space charge effect. Kuti uderedze pesvedzero yenzvimbo yekuchaja mhedzisiro, zvinodikanwa kudzikisa mafotoelectrons ari mune yega yega pulse uchichengetedza inogara inogara photon flux, saka zvinodikanwa kutyaira iyolaserine yakakwira yekudzokorora frequency kuburitsa yakanyanyisa ultraviolet mwenje sosi ine yakakwira yekudzokorora frequency.
Resonance yakawedzera cavity tekinoroji inoziva chizvarwa cheyakanyanya kurongeka harmonics paMHz kudzokorora frequency
Kuti vawane yakanyanyisa ultraviolet mwenje sosi ine mwero wekudzokorora unosvika 60 MHz, timu yaJones paYunivhesiti yeBritish Columbia muUnited Kingdom yakaita yakarongeka yakarongeka chizvarwa mufemtosecond resonance enhancement cavity (fsEC) kuti ibudirire. yakanyanyisa ultraviolet mwenje sosi uye yakaiisa kune yakagadziriswa nguva-yakagadziriswa erekitironi spectroscopy (Tr-ARPES) kuyedza. Chiedza chechiedza chinokwanisa kuendesa photon flux inodarika 1011 nhamba dzephoton pasekondi imwe chete ine harmonic pakudzokorora kwe 60 MHz musimba re 8 kusvika 40 eV. Vakashandisa ytterbium-doped fiber laser system senge sosi yembeu yefsEC, uye yakadzora pulse maitiro kuburikidza neyakagadzirirwa laser system dhizaini kudzikisa mutakuri envelope offset frequency (fCEO) ruzha uye kuchengetedza yakanaka pulse compression maitiro pakupera kweketani yeamplifier. Kuti uwane yakagadzikana resonance kukwidziridzwa mukati mefsEC, vanoshandisa matatu servo control loops yekudzora mhinduro, zvichikonzera kudzikamisa kunoshanda pamadhigirii maviri erusununguko: nguva yekutenderera yekutenderera bhasikoro mukati mefsEC inofanana nelaser pulse nguva, uye chikamu chekuchinja. yemagetsi emutakuri wemunda zvine ruremekedzo kune pulse envelope (kureva, mutakuri envelope chikamu, ϕCEO).
Nekushandisa krypton gasi segasi rinoshanda, timu yekutsvagisa yakawana chizvarwa chepamusoro-order harmonics mufsEC. Vakaita Tr-ARPES zviyero zvegraphite uye vakacherechedza kukurumidza kupisa uye kwakatevera kunonoka kusanganiswa kwevanhu vasina-thermally excited electron populations, pamwe chete nemasimba ematunhu asina kupisa zvakananga pedyo neFermi level pamusoro pe0.6 eV. Ichi chitubu chechiedza chinopa chishandiso chakakosha chekudzidza chimiro chemagetsi chezvakaoma zvinhu. Nekudaro, chizvarwa cheyakanyanya kurongeka maharmonics mufsEC ine zvakakwirira kwazvo zvinodiwa zvekuratidzira, kupararira muripo, kugadziridzwa kwakanaka kwegomba kureba uye kukiya kwekubatanidza, izvo zvichakanganisa zvakanyanya kukwidziridzwa kwakawanda kweiyo resonance-inosimudzira mhango. Panguva imwecheteyo, iyo isiri-linear chikamu chemhinduro ye plasma panzvimbo yepakati yegomba zvakare idambudziko. Naizvozvo, pari zvino, rudzi urwu rwemwenje sosi haruna kuve yakanyanya kunyanyisa ultraviolethigh harmonic chiedza sosi.
Nguva yekutumira: Kubvumbi-29-2024