Hauv kev tshaj tawm tseem ceeb nyob rau yav tsaus ntuj ntawm Lub Kaum Hli 3, 2023, Nobel nqi zog hauv Physics rau xyoo 2023 tau nthuav tawm, lees paub qhov kev koom tes zoo ntawm peb tus kws tshawb fawb uas tau ua lub luag haujlwm tseem ceeb ua cov pioneer hauv thaj av ntawm attosecond laser technology.

Lub sij hawm "attosecond laser" muab nws lub npe los ntawm lub sijhawm luv luv uas nws ua haujlwm rau, tshwj xeeb hauv kev txiav txim ntawm attoseconds, sib xws rau 10^-18 vib nas this. Txhawm rau nkag siab qhov tseem ceeb ntawm cov thev naus laus zis no, qhov kev nkag siab tseem ceeb ntawm qhov attosecond signifies yog qhov tseem ceeb. Ib qho attosecond stands li ib feeb feeb ntawm lub sij hawm, tsim ib billionth ntawm ib billionth ntawm ib tug thib ob nyob rau hauv lub dav cov ntsiab lus ntawm ib tug thib ob. Txhawm rau muab qhov no rau hauv qhov kev xav, yog tias peb piv qhov thib ob mus rau lub roob siab siab, ib qho attosecond yuav zoo ib yam li ib qho nplej ntawm cov xuab zeb nestled ntawm lub roob. Nyob rau hauv lub caij ntuj no lub caij ntuj sov no, txawm lub teeb muaj peev xwm taug qab ib tug deb sib npaug rau qhov loj ntawm ib tug neeg atom. Los ntawm kev siv attosecond lasers, cov kws tshawb fawb tau txais lub peev xwm tsis tau pom dua los tshuaj xyuas thiab tswj xyuas qhov sib txawv ntawm cov hluav taws xob nyob hauv cov qauv atomic, zoo li lub thav duab-los ntawm-ncej qeeb-suab replay hauv cov yeeb yaj kiab ua ntu zus, yog li delving rau hauv lawv cov kev sib tham.

Attosecond laserssawv cev rau qhov tseem ceeb ntawm kev tshawb fawb dav dav thiab kev sib koom ua ke los ntawm cov kws tshawb fawb, uas tau siv cov ntsiab lus ntawm nonlinear optics los tsim cov lasers ultrafast. Lawv qhov kev tshwm sim tau muab rau peb nrog lub ntsiab lus zoo tshaj plaws rau kev soj ntsuam thiab tshawb xyuas cov txheej txheem dynamic transpiring hauv atoms, molecules, thiab txawm tias electrons hauv cov khoom siv.

Txhawm rau kom meej meej qhov xwm txheej ntawm attosecond lasers thiab txaus siab rau lawv cov yam ntxwv tsis sib xws hauv kev sib piv rau cov pa lasers, nws yog qhov tsim nyog los tshawb nrhiav lawv cov categorization nyob rau hauv dav "laser tsev neeg." Kev faib tawm los ntawm lub wavelength qhov chaw attosecond lasers feem ntau nyob rau hauv ntau ntawm ultraviolet mus rau mos X-ray frequencies, signifying lawv notably luv wavelengths nyob rau hauv sib piv rau cov pa lasers. Nyob rau hauv cov nqe lus ntawm cov zis hom, attosecond lasers poob nyob rau hauv qeb ntawm pulse lasers, yam ntxwv los ntawm lawv heev luv luv mem tes ntev. Txhawm rau kos ib qho piv txwv rau kev pom tseeb, ib tus tuaj yeem pom cov lasers txuas ntxiv-yoj ib yam li lub teeb nyem emitting ib lub teeb nruam ntawm lub teeb, thaum lub lasers pulsed zoo li lub teeb strobe, hloov ceev ceev ntawm lub sij hawm ntawm illumination thiab tsaus ntuj. Nyob rau hauv qhov tseeb, attosecond lasers qhia ib tug cwj pwm pulsating nyob rau hauv lub illumination thiab tsaus ntuj nti, tab sis lawv txoj kev hloov ntawm ob lub xeev transpires ntawm ib tug xav tsis thoob zaus, mus txog lub realm ntawm attoseconds.

Ntxiv categorization los ntawm lub hwj chim muab lasers rau hauv qis-fais fab, nruab nrab-lub zog, thiab high-power brackets. Attosecond lasers ua tiav lub zog siab kawg vim lawv lub sijhawm luv luv, ua rau lub zog siab tshaj plaws (P) - txhais tau tias yog qhov siv zog ntawm ib lub sijhawm (P = W / t). Txawm hais tias ib tus neeg attosecond laser pulses yuav tsis muaj lub zog loj heev (W), lawv lub sijhawm luv luv (t) muab rau lawv nrog lub zog siab siab.

Nyob rau hauv cov nqe lus ntawm daim ntawv thov domains, lasers span ib spectrum encompassing industrial, kho mob, thiab scientific daim ntaub ntawv. Attosecond lasers feem ntau pom lawv cov niche nyob rau hauv lub cheeb tsam ntawm kev tshawb fawb, tshwj xeeb tshaj yog nyob rau hauv kev tshawb fawb ntawm evolving phenomena sai sai nyob rau hauv lub domains ntawm physics thiab chemistry, muab lub qhov rais mus rau hauv lub microcosmic ntiaj teb no txoj kev ceev ceev ceev.

Categorization los ntawm laser nruab nrab delineates lasers li gas lasers, solid-state lasers, kua lasers, thiab semiconductor lasers. Lub cim ntawm attosecond lasers feem ntau hinges ntawm cov pa laser media, capitalizing ntawm nonlinear optical teebmeem rau engender high-order harmonics.

Nyob rau hauv summation, attosecond lasers tsim ib tug tshwj xeeb chav kawm ntawv ntawm luv-pulse lasers, txawv los ntawm lawv extraordinarily luv luv mem tes ntev, feem ntau ntsuas nyob rau hauv attoseconds. Yog li ntawd, lawv tau dhau los ua cov cuab yeej tseem ceeb rau kev soj ntsuam thiab tswj cov txheej txheem ultrafast dynamic ntawm electrons nyob rau hauv atoms, molecules, thiab cov khoom siv.

Cov txheej txheem nthuav dav ntawm Attosecond Laser Generation

Attosecond laser technology sawv ntawm lub hauv ntej ntawm kev tshawb fawb innovation, khav theeb intriguingly nruj txheej txheem rau nws tiam. Txhawm rau piav qhia qhov tsis sib xws ntawm attosecond laser tiam, peb pib nrog kev nthuav qhia ntawm nws cov hauv paus ntsiab lus, ua raws li cov lus piv txwv zoo los ntawm cov kev paub niaj hnub. Cov neeg nyeem unversed nyob rau hauv lub intricacies ntawm lub physics cuam tshuam yuav tsum tsis txhob poob siab, raws li cov lus piv txwv los ua kom lub hauv paus physics ntawm attosecond lasers siv tau.

Cov txheej txheem tiam ntawm attosecond lasers feem ntau yog nyob ntawm cov txheej txheem hu ua High Harmonic Generation (HHG). Ua ntej, lub beam ntawm high-intensity femtosecond (10^-15 vib nas this) laser pulses yog nruj nreem tsom mus rau lub hom phiaj gaseous khoom. Nws tsim nyog sau cia tias femtosecond lasers, zoo li attosecond lasers, qhia cov yam ntxwv ntawm kev muaj lub sijhawm luv luv thiab lub zog siab. Nyob rau hauv kev cuam tshuam ntawm lub tshav laser khaus, electrons nyob rau hauv cov pa roj atoms yog momentary liberated los ntawm lawv atomic nuclei, transiently nkag mus rau hauv lub xeev ntawm dawb electrons. Raws li cov electrons oscillate nyob rau hauv teb rau lub laser teb, lawv nws thiaj li rov qab mus thiab recombine nrog lawv niam txiv atomic nuclei, tsim tshiab high-zog xeev.

Thaum lub sij hawm tus txheej txheem no, electrons txav ntawm qhov siab tshaj plaws, thiab thaum recombination nrog lub atomic nuclei, lawv tso lub zog ntxiv nyob rau hauv daim ntawv ntawm siab harmonic emissions, manifesting li high-zog photons.

Cov zaus ntawm cov tshiab tsim tawm high-zog photons yog qhov sib npaug ntawm cov thawj laser zaus, tsim qhov uas hu ua high-order harmonics, qhov "harmonics" qhia ntau zaus uas yog qhov sib npaug ntawm qhov qub zaus. Txhawm rau kom tau txais attosecond lasers, nws yuav tsum tau lim thiab tsom mus rau cov kev txiav txim siab siab, xaiv cov kev sib haum xeeb tshwj xeeb thiab tsom mus rau qhov chaw focal. Yog tias xav tau, cov txheej txheem pulse compression tuaj yeem ua kom luv luv ntawm lub sijhawm pulse, yielding ultra-luv pulses nyob rau hauv attosecond range. Pom tau tias, tiam ntawm attosecond lasers tsim cov txheej txheem sophisticated thiab multifaceted, xav tau qib siab ntawm kev txawj ntse thiab cov cuab yeej tshwj xeeb.

Txhawm rau demystify cov txheej txheem intricate no, peb muab ib qho piv txwv piv txwv uas nyob rau hauv cov xwm txheej niaj hnub:

High-Intensity Femtosecond Laser Pulses:

Kev xav muaj lub peev xwm tshwj xeeb tshaj plaws uas muaj peev xwm ntawm lub pob zeb nrawm nrawm nrawm, zoo li lub luag haujlwm ua si los ntawm kev siv zog femtosecond laser pulses.

Gaseous Target Khoom:

Daim duab ib lub cev nyob ntsiag to ntawm cov dej uas cim cov khoom siv lub hom phiaj gaseous, qhov twg txhua tee dej sawv cev rau myriad gas atoms. Qhov kev ua ntawm propelling pob zeb rau hauv lub cev ntawm cov dej no analogously tsom qhov cuam tshuam ntawm high-siv femtosecond laser pulses ntawm cov khoom siv gaseous.

Electron Motion thiab Recombination (Lub cev hloov pauv lub cev):

Thaum femtosecond laser pulses cuam tshuam cov roj atoms nyob rau hauv cov khoom siv gaseous, ib qho tseem ceeb ntawm cov hluav taws xob sab nraud zoo siab rau lub xeev uas lawv tshem tawm ntawm lawv cov atomic nuclei, tsim lub xeev zoo li plasma. Raws li lub zog lub zog tom qab poob qis (vim lub laser pulses yog inherently pulsed, featuring intervals of cessation), cov txheej electrons rov qab mus rau lawv thaj tsam ntawm lub atomic nuclei, tso high-zog photons.

High Harmonic Generation:

Xav txog txhua zaus cov dej ntws rov qab los rau ntawm lub pas dej, nws tsim ripples, zoo li kev sib raug zoo siab hauv attosecond lasers. Cov ripples no muaj ntau zaus thiab amplitudes tshaj qhov qub ripples tshwm sim los ntawm thawj femtosecond laser pulse. Thaum lub sij hawm HHG txheej txheem, ib tug haib laser beam, zoo li tsis tu ncua tossing pob zeb, illuminates ib lub hom phiaj roj, zoo li lub pas dej nto. Qhov no khaus laser teb propels electrons nyob rau hauv cov pa, piv rau ripples, deb ntawm lawv niam txiv atoms thiab ces rub lawv rov qab. Txhua lub sij hawm ib tug electron rov qab mus rau lub atom, nws emits ib tug tshiab laser beam nrog ib tug ntau zaus, akin rau ntau intricate ripple qauv.

Filtering thiab Focusing:

Kev sib txuas tag nrho cov teeb pom kev zoo tshiab no ua rau muaj qhov sib txawv ntawm ntau yam xim (frequencies lossis wavelengths), qee qhov uas yog lub laser attosecond. Txhawm rau cais cov ripple qhov ntau thiab tsawg zaus, koj tuaj yeem ntiav cov lim tshwj xeeb, zoo li xaiv cov ripples uas xav tau, thiab siv lub iav tsom iav kom tsom mus rau thaj chaw tshwj xeeb.

Pulse Compression (yog tias tsim nyog):

Yog tias koj tsom mus rau kev nthuav tawm ripples sai dua thiab luv dua, koj tuaj yeem ua kom lawv cov kev nthuav tawm sai dua siv cov cuab yeej tshwj xeeb, txo lub sij hawm txhua ripple kav. Lub cim ntawm attosecond lasers koom nrog kev sib tshuam ntawm cov txheej txheem. Txawm li cas los xij, thaum tawg thiab pom, nws ua kom nkag siab ntau dua.