原子在兩色組合激光場(chǎng)中產(chǎn)生的單個(gè)阿秒脈沖.pdf

1、西北師范大學(xué)碩士學(xué)位論文原子在兩色組合激光場(chǎng)中產(chǎn)生的單個(gè)阿秒脈沖姓名：葉小亮申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：原子與分子物理指導(dǎo)教師：周效信200905西北師范大學(xué)碩士學(xué)位論文AbstractTheattosecondpulseisarobusttooltoresolvemanipulateultrafastelectronicprocesses.InthepresentyearsTheadventofattosecondpulsesprovid

2、esthepossibilityofprobingultrafastelectrondynamicsinatomsmolecules.Itiswellknownthattheinteractionofintenselaserfieldwithatomsmoleculescanleadtohighderharmonicgeneration(HHG).Atypicalhighderharmonicspectrumshowsthatwitht

3、heincreaseofharmonicderthesignalintensitiesfalloffdrasticallyfthefirstfewlowdersthentheintensitiesremainalmostconstantfmanydersthatfmaplateaufinallytheintensitysabruptlyfthehighestderswhichhavenamedthecutoff.Theappearanc

4、eofplateaustructuresfromHHGpowerspectramakeHHGpossibleassourcesofradiationinXrayXUVareasfurthermeHHGisapreferredsourcefthegenerationofattosecondpulse.InthechapterbysolvingthetimedependentSchrdingerequationwithsplitoperat

5、methodwestudythehighharmonicsofonedimensionheliumatomexposedtothetwocollaserfieldcomposedofIRfieldUVfieldanalyzetheacteristicsoftheattosecondpulsewhichisproducedbythehighderharmonics.Itisfoundthatthewidthoftheattosecondp

6、ulseisshtenedbyincreasingintensityofIRfieldinthecombinedlaserfield.ByadjustingthetimedelayoftwolaserswecanenhancethecontributionofoneelectrontrajectysuppresstheotherelectrontrajectyThenwecanobtainanisolatedsub100aspulse.

7、MeoverBysolvingthetimedependentSchrdingerequationwithsplitoperatmethodwestudythehighharmonicsofonedimensionheliumatomexposedtothecombinedlaserfieldcomposedofIRfield、UVfieldastaticelectricfieldByaddingastaticelectricfield

8、tothetwocollaserfieldWefoundtheplateauofthehighderharmonicswillbebroadeninthepresenceofastaticelectricfield.Itisalsofoundthatthewidthoftheattosecondpulseisshtenedbyincreasingintensityofastaticelectricfieldinthecombinedla