Kufambira mberi mukushandiswa kwe ultraviolet yakanyanyatekinoroji yechiedza
Mumakore achangopfuura, masosi e-ultraviolet ane harmonic yakawanda akakwezva kutariswa kukuru mumunda we electron dynamics nekuda kwekubatana kwawo kwakasimba, nguva pfupi yekurova kwemoyo uye simba rakawanda re photon, uye akashandiswa muzvidzidzo zvakasiyana-siyana zve spectral uye mifananidzo. Nekufambira mberi kwetekinoroji, izvichiedza chinobvairi kukura ichienda pakudzokororwa kwakawanda, kubuda kwephoton kwakakwira, simba rephoton rakawanda uye upamhi hwekurova kwemoyo hupfupi. Kufambira mberi uku hakungogadzirisi chete kuyera kwezvinobva muchiedza cheultraviolet chakanyanya, asiwo kunopa mikana mitsva yekuvandudza tekinoroji mune ramangwana. Nokudaro, kudzidza kwakadzama uye kunzwisisa kwechiedza cheultraviolet chakanyanya kudzokorora kwakakosha zvikuru pakudzidza nekushandisa tekinoroji yemazuva ano.
Pakuyerwa kwe electron spectroscopy pa femtosecond nenguva uye attosecond, huwandu hwezviitiko zvinoyerwa mu beam rimwe chete hahuwanzo kukwana, zvichiita kuti matsime echiedza adzokororwe zvishoma asakwane kuwana nhamba dzakavimbika. Panguva imwe chete, chiedza chine photon flux yakaderera chichaderedza chiyero chesignal-to-noise che microscopic imaging panguva shoma yekuratidzwa. Kuburikidza nekutsvaga nekuyedza, vaongorori vakaita shanduko dzakawanda mukugadzirwa kwe yield optimization uye transmission design ye high repetition frequency extreme ultraviolet light. Tekinoroji yepamusoro yekuongorora spectral pamwe chete ne high repetition frequency extreme ultraviolet light source yakashandiswa kuwana high usahihi kuyerwa kwechimiro chezvinhu uye electronic dynamic process.
Kushandiswa kwezviwanikwa zvechiedza cheultraviolet chakanyanya, zvakaita sekuyera kwe electron spectroscopy (ARPES), kunoda chiedza cheultraviolet chakanyanya kuti chivhenekere muenzaniso. Maerekitironi ari pamusoro pemuenzaniso anokurudzirwa kuti arambe achienderera mberi nechiedza cheultraviolet chakanyanya, uye kinetic energy uye emission Angle ye photoelectrons ine ruzivo rwechimiro che band yemuenzaniso. Electron analyzer ine Angle resolution function inogamuchira ma photoelectrons akasvinwa uye inowana chimiro che band pedyo ne valence band yemuenzaniso. Kune frequency yakaderera yekudzokorora, chiedza cheultraviolet chakanyanya, nekuti single pulse yayo ine nhamba yakakura yema photons, ichamutsa nhamba yakawanda yema photoelectrons pamusoro pemuenzaniso munguva pfupi, uye Coulomb inosangana ichaunza kuwedzera kukuru kwekupararira kwe photoelectron kinetic energy, iyo inonzi space charge effect. Kuti uderedze simba re space charge effect, zvakakosha kuderedza ma photoelectrons ari mu pulse yega yega uchichengetedza constant photon flux, saka zvakakosha kufambisalaserine kudzokorora kwakawanda kuti ibudise chiedza cheultraviolet chakanyanya uye kudzokorora kwakawanda.
Tekinoroji yekuwedzera resonance cavity inoita kuti pave nekugadzirwa kwemaharmonics epamusoro-soro paMHz repetition frequency
Kuti vawane chiedza cheultraviolet chakanyanya chine mwero wekudzokorora unosvika 60 MHz, timu yeJones paYunivhesiti yeBritish Columbia muUnited Kingdom yakaita hunyanzvi hwepamusoro hwekugadzira harmonic mu femtosecond resonance enhancement cavity (fsEC) kuti vawane chiedza cheultraviolet chakanyanya uye vakachishandisa pakuedza kwe time-resolved angular resolved electron spectroscopy (Tr-ARPES). Chitubu chechiedza ichi chinokwanisa kupa photon flux yenhamba dzinopfuura 1011 dze photon pasekondi ne harmonic imwe chete pamwero wekudzokorora we60 MHz muhuwandu hwesimba hwe8 kusvika 40 eV. Vakashandisa ytterbium-doped fiber laser system senzvimbo yembeu ye fsEC, uye vakadzora hunhu hwepulse kuburikidza nekugadzira laser system yakagadziriswa kuderedza ruzha rwe carrier envelope offset frequency (fCEO) uye kuchengetedza hunhu hwakanaka hwepulse compression pakupera kwe amplifier chain. Kuti vawane kusimudzira kwakasimba kwe resonance mukati me fsEC, vanoshandisa marobho matatu ekutonga kweservo kudzora mhinduro, zvichikonzera kugadzikana kuri kushanda pamadhigirii maviri erusununguko: nguva yekudzoka kwe pulse cycling mukati me fsEC inoenderana nenguva ye laser pulse, uye phase shift ye electric field carrier maererano ne pulse envelope (kureva, carrier envelope phase, ϕCEO).
Nekushandisa gasi rekrypton segasi rinoshanda, timu yekutsvagisa yakakwanisa kugadzira maharmonics emhando yepamusoro mu fsEC. Vakayera Tr-ARPES graphite uye vakaona kukurumidza kupisa uye kudzokororwa zvishoma nezvishoma kwema electron populations asina kupisa, pamwe nekuchinjana kwemamiriro ekunze asina kupisa pedyo neFermi level iri pamusoro pe 0.6 eV. Chiedza ichi chinopa chishandiso chakakosha chekudzidza chimiro chemagetsi chezvinhu zvakaoma. Zvisinei, kugadzirwa kwemaharmonics emhando yepamusoro mu fsEC kune zvinodiwa zvakanyanya zve reflectivity, dispersion compensation, fine adjustment ye cavity length uye synchronization locking, izvo zvichakanganisa zvakanyanya enhancement multiple ye resonance-enhanced cavity. Panguva imwe chete, nonlinear phase response ye plasma panzvimbo ye focal ye cavity idambudzikowo. Saka, pari zvino, rudzi urwu rwechiedza haruna kuva mainstream extreme ultraviolet.chiedza chakawanda che harmonic.
Nguva yekutumira: Kubvumbi-29-2024