Txheej txheem cej luam ntawm pulsed lasers

Txheej txheem cej luam ntawmpulsed lasers

Txoj kev ncaj ncees tshaj plaws los tsimlaserpulses yog ntxiv ib qho modulator rau sab nraud ntawm lub laser txuas ntxiv. Txoj kev no tuaj yeem tsim qhov ceev tshaj plaws picosecond mem tes, txawm hais tias yooj yim, tab sis pov tseg lub teeb lub zog thiab lub zog ncov tsis tuaj yeem tshaj lub teeb lub zog tas li. Yog li ntawd, ib txoj hauv kev zoo dua los ua kom muaj laser pulses yog hloov kho hauv lub laser kab noj hniav, khaws cia lub zog ntawm lub sijhawm ntawm lub tsheb ciav hlau pulse thiab tso tawm ntawm lub sijhawm. Plaub txoj kev siv los tsim cov pulses los ntawm laser kab noj hniav modulation yog nce hloov, Q-hloov (tsis hloov), kab noj hniav, thiab hom-locking.

Qhov hloov pauv tau tsim cov pulses luv luv los ntawm kev hloov pauv lub zog ntawm lub twj tso kua mis. Piv txwv li, semiconductor nce-hloov lasers tuaj yeem tsim cov pulses los ntawm ob peb nanoseconds mus rau ib puas picoseconds los ntawm kev hloov kho tam sim no. Txawm hais tias lub zog pulse tsis tshua muaj, txoj kev no yog qhov hloov tau yooj yim, xws li muab kev hloov pauv zaus thiab mem tes dav. Nyob rau hauv 2018, cov kws tshawb fawb ntawm University of Tokyo tau tshaj tawm txog femtosecond nce-switched semiconductor laser, sawv cev rau kev ua tiav hauv 40-xyoo kev siv lub raj mis.

Lub zog nanosecond pulses feem ntau yog tsim los ntawm Q-hloov lasers, uas tau tawm hauv ntau qhov kev mus ncig hauv kab noj hniav, thiab lub zog pulse yog nyob rau hauv ntau ntawm ob peb millijoules mus rau ob peb joules, nyob ntawm qhov loj ntawm qhov system. Lub zog nruab nrab (feem ntau hauv qab 1 μJ) picosecond thiab femtosecond pulses yog tsim los ntawm hom-xauv lasers. Muaj ib los yog ntau dua ultrashort pulses nyob rau hauv lub laser resonator uas voj voog tsis tu ncua. Txhua qhov intracavity mem tes xa cov mem tes los ntawm daim iav tso zis sib txuas, thiab qhov zaus feem ntau yog nyob nruab nrab ntawm 10 MHz thiab 100 GHz. Daim duab hauv qab no qhia tau hais tias tag nrho ib txwm dispersion (ANDi) dissipative soliton femtosecondfiber ntau laser ntaus ntawv, feem ntau ntawm cov uas tuaj yeem tsim tau siv Thorlabs tus qauv cov khoom (fiber, lens, mount thiab displacement table).

Cavity emptying txheej txheem yuav siv tau rauQ-hloov laserskom tau txais luv luv pulses thiab hom-xauv lasers kom muaj zog pulse nrog qis dua.

Time domain thiab zaus domain pulses
Cov duab linear ntawm cov mem tes nrog lub sij hawm feem ntau kuj yooj yim thiab tuaj yeem qhia los ntawm Gaussian thiab sech² zog. Pulse lub sij hawm (tseem hu ua mem tes dav) feem ntau qhia los ntawm ib nrab-qhov siab dav (FWHM) tus nqi, uas yog, qhov dav thoob plaws uas lub optical hwj chim yog tsawg kawg yog ib nrab ntawm lub ncov lub hwj chim; Q-hloov laser generates nanosecond luv pulses los ntawm
Hom-locked lasers tsim ultra-luv pulses (USP) nyob rau hauv qhov kev txiav txim ntawm kaum ntawm picoseconds rau femtoseconds. Cov hluav taws xob ceev ceev tsuas tuaj yeem ntsuas txog kaum tawm picoseconds, thiab luv luv pulses tsuas tuaj yeem ntsuas nrog cov thev naus laus zis nkaus xwb xws li autocorrelators, FROG thiab Kab laug sab. Thaum nanosecond lossis ntev pulses tsis tshua hloov lawv cov mem tes dav thaum lawv mus ncig, txawm tias nyob deb, ultra-luv pulses tuaj yeem cuam tshuam los ntawm ntau yam:

Dispersion tuaj yeem ua rau lub plawv dhia loj, tab sis tuaj yeem rov ua dua nrog qhov sib txawv dispersion. Cov duab hauv qab no qhia tau hais tias Thorlabs femtosecond pulse compressor them nyiaj li cas rau microscope dispersion.

Nonlinearity feem ntau tsis cuam tshuam ncaj qha rau lub mem tes dav, tab sis nws nthuav dav bandwidth, ua rau cov mem tes muaj kev cuam tshuam rau kev tawg thaum lub sij hawm nthuav tawm. Txhua hom fiber ntau, suav nrog lwm qhov kev tshaj tawm nrog kev txwv bandwidth, tuaj yeem cuam tshuam cov duab ntawm bandwidth lossis ultra-luv mem tes, thiab kev txo qis hauv bandwidth tuaj yeem ua rau lub sijhawm ntev; Kuj tseem muaj cov xwm txheej uas qhov dav pulse ntawm lub siab chirped mem tes ua luv luv thaum lub spectrum yuav nqaim.