Kev piav qhia txog cov lasers pulsed

Txheej txheem cej luam ntawmcov lasers pulsed

Txoj kev ncaj qha tshaj plaws los tsimlasercov pulses yog ntxiv ib qho modulator rau sab nraud ntawm lub laser txuas ntxiv mus. Txoj kev no tuaj yeem tsim cov picosecond pulse sai tshaj plaws, txawm hais tias yooj yim, tab sis pov tseg lub zog teeb thiab lub zog siab tshaj plaws tsis tuaj yeem tshaj lub zog teeb txuas ntxiv mus. Yog li ntawd, ib txoj hauv kev zoo dua los tsim cov laser pulses yog modulate hauv lub laser cavity, khaws cia lub zog thaum tawm ntawm lub tsheb ciav hlau pulse thiab tso nws thaum lub sijhawm. Plaub txoj hauv kev siv los tsim cov pulses los ntawm laser cavity modulation yog gain switching, Q-switching (loss switching), cavity emptying, thiab mode-locking.

Lub qhov hloov pauv nce tsim cov pulses luv luv los ntawm kev hloov kho lub zog twj tso kua mis. Piv txwv li, semiconductor gain-switched 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 qis, txoj kev no muaj kev ywj pheej heev, xws li muab qhov zaus rov ua dua thiab qhov dav pulse. Xyoo 2018, cov kws tshawb fawb ntawm University of Tokyo tau tshaj tawm txog femtosecond gain-switched semiconductor laser, uas sawv cev rau kev tawg hauv 40-xyoo kev lag luam bottleneck.

Feem ntau cov pulses nanosecond muaj zog yog tsim los ntawm Q-switched lasers, uas tau tso tawm hauv ntau qhov kev mus ncig hauv qhov, thiab lub zog pulse yog nyob rau hauv qhov ntau ntawm ntau millijoules rau ntau joules, nyob ntawm qhov loj ntawm lub system. Lub zog nruab nrab (feem ntau hauv qab 1 μJ) picosecond thiab femtosecond pulses feem ntau yog tsim los ntawm mode-locked lasers. Muaj ib lossis ntau ultrashort pulses hauv lub laser resonator uas voj voog tas mus li. Txhua lub intracavity pulse xa ib lub pulse los ntawm lub iav coupling tso zis, thiab qhov rov ua dua feem ntau yog ntawm 10 MHz thiab 100 GHz. Daim duab hauv qab no qhia txog kev sib cais tag nrho (ANDi) dissipative soliton femtosecondcov khoom siv laser fiber, feem ntau ntawm cov uas tuaj yeem tsim tau siv Thorlabs cov khoom txheem (fiber, lens, mount thiab displacement table).

Kev siv cov txheej txheem emptying cavity tuaj yeem siv rauQ-switched laserskom tau txais cov pulses luv dua thiab mode-locked lasers kom nce lub zog pulse nrog qis dua refrequency.

Lub sijhawm sau thiab zaus sau pulses
Cov duab linear ntawm lub pulse nrog lub sijhawm feem ntau yog qhov yooj yim thiab tuaj yeem qhia los ntawm Gaussian thiab sech² functions. Lub sijhawm pulse (tseem hu ua pulse width) feem ntau yog qhia los ntawm qhov siab ib nrab (FWHM) tus nqi, uas yog, qhov dav uas lub zog optical yog tsawg kawg yog ib nrab ntawm lub zog siab tshaj plaws; Q-switched laser tsim cov nanosecond luv luv pulses los ntawm
Cov lasers uas raug xauv hom tsim cov pulses luv luv heev (USP) raws li kaum tawm picoseconds mus rau femtoseconds. Cov khoom siv hluav taws xob ceev ceev tsuas yog ntsuas tau txog kaum tawm picoseconds, thiab cov pulses luv dua tsuas yog ntsuas tau nrog cov thev naus laus zis optical xws li autocorrelators, FROG thiab SPIDER. Txawm hais tias nanosecond lossis cov pulses ntev dua tsis tshua hloov lawv qhov dav ntawm pulse thaum lawv mus ncig, txawm tias nyob deb heev, cov pulses luv luv heev tuaj yeem cuam tshuam los ntawm ntau yam:

Kev tawg ua rau lub zog loj zuj zus, tab sis tuaj yeem rov ua kom nruj dua nrog qhov tawg ua rau sab nraud. Daim duab hauv qab no qhia txog Thorlabs femtosecond pulse compressor them rau qhov tawg ua rau lub tshuab microscope tawg.

Feem ntau nonlinearity tsis cuam tshuam ncaj qha rau qhov dav ntawm lub pulse, tab sis nws ua rau lub bandwidth dav dua, ua rau lub pulse yooj yim dua rau kev tawg thaum lub sijhawm nthuav dav. Txhua hom fiber, suav nrog lwm cov xov xwm nce nrog bandwidth tsawg, tuaj yeem cuam tshuam rau cov duab ntawm bandwidth lossis ultra-luv pulse, thiab qhov txo qis ntawm bandwidth tuaj yeem ua rau lub sijhawm dav dua; Kuj tseem muaj cov xwm txheej uas qhov dav ntawm lub pulse ntawm lub zog chirped luv dua thaum lub spectrum nqaim dua.