Laser yofulumira kwambiri ya sayansi ya attosecond

Laser yothamanga kwambiriza sayansi ya attosecond
Pakadali pano, ma attosecond pulses amapezeka makamaka kudzera mu high-order harmonic generation (HHG) yoyendetsedwa ndi ma strong fields. Kupangidwa kwawo kumatha kumveka ngati ma electron omwe amasinthidwa kukhala ion, kufulumizitsidwa, ndikugwirizanitsidwanso ndi mphamvu yamagetsi ya laser kuti atulutse mphamvu, motero amatulutsa ma attosecond XUV pulses.
Chifukwa chake, kutulutsa kwa attosecond kumakhudzidwa kwambiri ndi kukula kwa kugunda kwa mtima, mphamvu, kutalika kwa mafunde, ndi kuchuluka kwa kubwerezabwereza kwalaser yoyendetsa(Laser yothamanga kwambiri): Kufupika kwa pulse m'lifupi ndi kothandiza pakulekanitsa ma attosecond pulses, mphamvu zambiri zimathandizira ionization ndi magwiridwe antchito, kutalika kwa wavelength kumawonjezera mphamvu yodulira koma kumachepetsa kwambiri mphamvu yosinthira, ndipo kuchuluka kwa kubwerezabwereza kumawonjezera chiŵerengero cha chizindikiro-ku-phokoso koma kumachepetsedwa ndi mphamvu imodzi ya pulse. Ntchito zosiyanasiyana (monga electron microscopy, X-ray absorption spectroscopy, coincidence counting, ndi zina zotero) zimatsindika mosiyanasiyana pa attosecond pulse index, yomwe imayika patsogolo zofunikira zosiyanasiyana komanso zokwanira zoyendetsera ma laser. Kuwongolera magwiridwe antchito a ma laser oyendetsera ndikofunikira kuti agwiritsidwe ntchito mu sayansi ya attosecond.

Njira zinayi zazikulu zaukadaulo zowongolera magwiridwe antchito a laser yoyendetsa (Ultra fast laser)
1. Mphamvu yapamwamba: Yopangidwa kuti ithetse mphamvu yochepa yosinthira ya HHG ndikupeza ma pulse a attosecond apamwamba. Kusintha kwa ukadaulo kwasintha kuchoka pa banja la chirped pulse amplification (CPA) kupita ku banja la optical parametric amplification, kuphatikiza optical parametric chirped pulse amplification (OPCPA), dual chirped OPA (DC-OPA), frequency domain OPA (FOPA), ndi quasi phase matching OPCPA (QPCPA). Kuphatikizanso njira zopangira coherent beam synthesis (CBC) ndi pulse splitting amplification (DPA) kuti athetse zofooka zakuthupi za single channel amplifier, monga zotsatira za kutentha ndi kuwonongeka kosakhala kwa mzere, ndikukwaniritsa mphamvu ya Joule level.
2. M'lifupi mwa pulse: Yopangidwa kuti ipange ma pulse a attosecond omwe angagwiritsidwe ntchito kusanthula mphamvu zamagetsi, zomwe zimafuna ma pulse ochepa kapena ngakhale ang'onoang'ono komanso gawo lokhazikika la envelopu (CEP). Maukadaulo akuluakulu akuphatikizapo kugwiritsa ntchito njira zosagwirizana ndi mzere monga hollow core fiber (HCF), multi thin film (MPSC), ndi multi-channel cavity (MPC) kuti ichepetse m'lifupi mwa pulse kukhala lalifupi kwambiri. Kukhazikika kwa CEP kumayesedwa pogwiritsa ntchito f-2f interferometer ndipo kumachitika kudzera mu active feedback/feedforward (monga AOFS, AOPDF) kapena passive all-optical self stabilization mechanisms kutengera njira zosiyanasiyana zama frequency.
3. Kutalika kwa nthawi yayitali: Yopangidwa kuti ikankhire mphamvu ya photon yachiwiri ku gulu la "windo la madzi" kuti ijambule zithunzi za biomolecule. Njira zitatu zazikulu zaukadaulo ndi izi:
Kukulitsa kwa Optical parametric (OPA) ndi kufalikira kwake: Ndi yankho lalikulu mu utali wa mafunde a 1-5 μ m, pogwiritsa ntchito makhiristo monga BiBO ndi MgO: LN; >Makhiristo monga ZGP ndi LiGaS ₂ amafunikira pa gulu la mafunde a 5 μ m.
Kupanga Ma Frequency Osiyanasiyana (DFG) ndi Intra Pulse Differential Frequency (IPDFG): zimatha kupatsa magwero a mbewu kukhazikika kwa CEP.
Ukadaulo wa laser mwachindunji, monga ma laser a Cr: ZnS/Se transition metal doped chalcogenide, umadziwika kuti "mid infrared titanium safiro" ndipo uli ndi ubwino wokhala ndi kapangidwe kakang'ono komanso magwiridwe antchito apamwamba.
4. Kuchuluka kwa kubwerezabwereza: cholinga chake ndi kukweza chiŵerengero cha chizindikiro ndi phokoso komanso kugwiritsa ntchito bwino deta, komanso kuthana ndi zofooka za zotsatira za kuyitanitsa malo. Njira ziwiri zazikulu:
Ukadaulo wowonjezera ma cavity a Resonance: kugwiritsa ntchito ma cavity a resonant olondola kwambiri kuti kuwonjezere mphamvu yayikulu ya ma pulses obwerezabwereza a megahertz level kuti ayendetse HHG, kwagwiritsidwa ntchito m'magawo monga ma XUV frequency combs, koma kupanga ma pulses a attosecond okhaokha kumabweretsa mavuto.
Kuchuluka kwa kubwerezabwereza komansolaser yamphamvu kwambiriKuyendetsa mwachindunji, kuphatikiza OPCPA, fiber CPA kuphatikiza ndi nonlinear post compression, ndi thin film oscillator, kwakwaniritsa kupanga kwapadera kwa attosecond pulse pamlingo wobwerezabwereza wa 100 kHz.