Ultra ceev laser rau attosecond science

Laser ceev heevrau kev tshawb fawb txog attosecond
Tam sim no, cov attosecond pulses feem ntau tau txais los ntawm kev tsim cov harmonic siab (HHG) uas tsav los ntawm cov teb muaj zog. Lub ntsiab lus ntawm lawv tiam neeg tuaj yeem nkag siab tias yog cov electrons raug ionized, accelerated, thiab rov ua ke los ntawm lub zog laser fais fab kom tso tawm lub zog, yog li ntawd emitting attosecond XUV pulses.
Yog li ntawd, cov zis attosecond yog qhov rhiab heev rau qhov dav ntawm lub zog, lub zog, wavelength, thiab qhov rov ua dua ntawmtsav tsheb laser(Laser ceev heev): qhov dav ntawm lub zog luv dua yog qhov zoo rau kev cais cov attosecond pulses, lub zog siab dua txhim kho ionization thiab kev ua haujlwm zoo, qhov ntev dua wavelength ua rau lub zog txiav tawm tab sis txo qhov kev hloov pauv zoo, thiab qhov rov ua dua siab dua txhim kho qhov sib piv ntawm lub teeb liab thiab suab nrov tab sis raug txwv los ntawm lub zog ib leeg. Cov ntawv thov sib txawv (xws li electron microscopy, X-ray absorption spectroscopy, coincidence counting, thiab lwm yam) muaj ntau qhov tseem ceeb ntawm attosecond pulse index, uas tso tawm cov kev cai sib txawv thiab kev xav tau rau kev tsav tsheb lasers. Kev txhim kho kev ua tau zoo ntawm kev tsav tsheb lasers yog qhov tseem ceeb rau kev siv hauv kev tshawb fawb attosecond.

Plaub txoj kev siv tshuab tseem ceeb los txhim kho kev ua haujlwm ntawm kev tsav tsheb lasers (Ultra fast laser)
1. Lub zog siab dua: Tsim los kov yeej qhov kev hloov pauv qis ntawm HHG thiab tau txais cov pulses attosecond siab. Kev hloov pauv thev naus laus zis tau hloov pauv ntawm cov chirped pulse amplification (CPA) ib txwm mus rau tsev neeg optical parametric amplification, suav nrog optical parametric chirped pulse amplification (OPCPA), dual chirped OPA (DC-OPA), frequency domain OPA (FOPA), thiab quasi phase matching OPCPA (QPCPA). Ntxiv kev sib txuas ua ke ntawm coherent beam synthesis (CBC) thiab pulse splitting amplification (DPA) synthesis cov txheej txheem los kov yeej cov kev txwv ntawm cov amplifiers ib channel, xws li cov teebmeem thermal thiab kev puas tsuaj nonlinear, thiab ua tiav Joule theem zog tso zis.
2. Qhov dav ntawm lub zog luv dua: Tsim los tsim cov attosecond pulses cais uas siv tau los tshuaj xyuas cov dynamics hluav taws xob, xav tau ob peb lossis txawm tias sub-periodic tsav tsheb pulses thiab stable carrier envelope phase (CEP). Cov thev naus laus zis tseem ceeb suav nrog kev siv cov txheej txheem nonlinear post compression xws li hollow core fiber (HCF), multi thin film (MPSC), thiab multi-channel cavity (MPC) los compress qhov dav ntawm lub zog kom luv heev. CEP stability yog ntsuas siv f-2f interferometer thiab ua tiav los ntawm kev tawm tswv yim / feedforward (xws li AOFS, AOPDF) lossis passive all-optical self stabilization mechanisms raws li cov txheej txheem sib txawv zaus.
3. Qhov ntev dua ntawm lub teeb: Tsim los thawb lub zog photon attosecond mus rau "qhov rai dej" rau kev thaij duab biomolecule. Peb txoj kev siv tshuab tseem ceeb yog:
Kev ua kom pom tseeb ntawm qhov muag (OPA) thiab nws cov cascade: Nws yog qhov kev daws teeb meem tseem ceeb hauv 1-5 μ m wavelength ntau yam, siv cov siv lead ua xws li BiBO thiab MgO: LN; > Cov siv lead ua xws li ZGP thiab LiGaS ₂ yog qhov xav tau rau 5 μ m wavelength band.
Kev Tsim Zaus Sib Txawv (DFG) thiab Intra Pulse Differential Frequency (IPDFG): tuaj yeem muab cov noob cog nrog kev ruaj khov CEP passive.
Cov thev naus laus zis laser ncaj qha, xws li Cr: ZnS/Se transition metal doped chalcogenide lasers, yog hu ua "mid infrared titanium sapphire" thiab muaj qhov zoo ntawm cov qauv me me thiab kev ua haujlwm siab.
4. Tus nqi rov ua dua siab dua: tsom mus rau kev txhim kho qhov sib piv ntawm lub teeb liab thiab suab nrov thiab kev ua haujlwm tau cov ntaub ntawv, thiab daws cov kev txwv ntawm cov teebmeem ntawm qhov chaw them. Ob txoj hauv kev tseem ceeb:
Resonance enhanced cavity technology: siv cov high-precision resonant cavities los txhim kho lub zog siab tshaj plaws ntawm megahertz qib repetitive frequency pulses los tsav HHG, tau siv rau hauv cov teb xws li XUV frequency combs, tab sis tsim cov attosecond pulses cais tseem ua rau muaj kev cov nyom.
Tus nqi rov ua dua siab thiablaser muaj zog heevkev tsav tsheb ncaj qha, suav nrog OPCPA, fiber CPA ua ke nrog nonlinear post compression, thiab thin film oscillator, tau ua tiav kev tsim hluav taws xob attosecond cais ntawm qhov rov ua dua ntawm 100 kHz.