Spektrālo profilu izmaiņas atomu mijiedarbībās ar koherenta lāzeru starojuma impulsiem: caurlidošanas laika un ietērpto stāvokļu interferences efekti
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Latvijas Universitāte
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Abstract
Darbs aplūko divus fundamentālus efektus atomu mijiedarbībā ar koherentiem lāzera impulsiem: ierobežota caurlidošanas laika radīto spektrālā profila paplašināšanos un ietērpto stāvokļu interferenci. Darbā tiek eksperimentāli nodemonstrēts, ka
(i) spektrāllīniju paplašinājums, kas rodas ierobežota caurlidošanas laika dēļ, ievērojami pārsniedz dabiskā kontūra platumu un
(ii) vienlaicīgā atoma mijiedarbībā ar diviem lāzeru impulsiem notiek ietērpto stāvokļu interference, kas izpaužas kā oscilāciju struktūras parādīšanās lāzeru ierosmes spektros.
Minētie efekti tiek nodemonstrēti, uzņemot Na atomu un Na 2 molekulu ierosmes spektrus trīslīmeņu pakāpienveida shēmās. Eksperimenti tiek veikti Na/Na 2 atomu/molekulu virsskaņas kūļu iekārtā, kurā atomi un molekulas tiek ierosināti ar diviem pretēji vērstiem
un fokusētiem lāzeru staru kūļiem.
Two fundamental processes upon interacion of atoms with coherent laser radiation pulses are investigated: transit time broadening and laser dressed state interference. It is demonstrated that (i) spectral line broadening that arises from a finite transit time notably exceeds the natural line width and (ii) upon simultaneous interaction of atom with two laser pulses laser dressed state interference, which is observed as an oscillating pattern in the excitation spectra, is created. Both effects are investigated by measuring excitation spectra of Na atoms and Na$_2$ molecules in several three-level ladder excitation schemes. Experiments are performed on a Na/Na$_2$ supersonic beam, where atoms and molecules are excited by two counterpropagating and focused laser beams.
Two fundamental processes upon interacion of atoms with coherent laser radiation pulses are investigated: transit time broadening and laser dressed state interference. It is demonstrated that (i) spectral line broadening that arises from a finite transit time notably exceeds the natural line width and (ii) upon simultaneous interaction of atom with two laser pulses laser dressed state interference, which is observed as an oscillating pattern in the excitation spectra, is created. Both effects are investigated by measuring excitation spectra of Na atoms and Na$_2$ molecules in several three-level ladder excitation schemes. Experiments are performed on a Na/Na$_2$ supersonic beam, where atoms and molecules are excited by two counterpropagating and focused laser beams.