Tshwj xeeb ultrafast laser ib feem

Tshwj xeeblaser ceev heevib feem

Cov yam ntxwv tshwj xeeb ntawm ultrafastcov lasers
Lub sijhawm luv luv ntawm cov lasers ultrafast muab cov khoom tshwj xeeb no uas sib txawv ntawm cov lasers ntev-pulse lossis continuous-wave (CW). Yuav kom tsim tau lub sijhawm luv luv, yuav tsum muaj bandwidth dav dav. Lub pulse zoo li thiab central wavelength txiav txim siab qhov bandwidth tsawg kawg nkaus uas yuav tsum tau tsim cov pulses ntawm lub sijhawm tshwj xeeb. Feem ntau, qhov kev sib raug zoo no tau piav qhia hauv cov nqe lus ntawm cov khoom lag luam time-bandwidth (TBP), uas yog los ntawm txoj cai tsis paub meej. TBP ntawm Gaussian pulse yog muab los ntawm cov mis hauv qab no: TBPGaussian = ΔτΔν≈0.441
Δτ yog lub sijhawm ntawm lub zog thiab Δv yog qhov zaus bandwidth. Hauv qhov tseem ceeb, qhov sib npaug qhia tau hais tias muaj kev sib raug zoo ntawm spectrum bandwidth thiab lub sijhawm ntawm lub zog, txhais tau tias thaum lub sijhawm ntawm lub zog txo qis, qhov bandwidth uas xav tau los tsim lub zog ntawd nce ntxiv. Daim duab 1 qhia txog qhov tsawg kawg nkaus bandwidth uas xav tau los txhawb ntau lub sijhawm sib txawv ntawm lub zog.

Daim Duab 1: Qhov tsawg kawg nkaus spectral bandwidth xav tau los txhawb nqacov laser pulsesntawm 10 ps (ntsuab), 500 fs (xiav), thiab 50 fs (liab)

Cov teeb meem kev siv tshuab ntawm ultrafast lasers
Qhov dav spectral bandwidth, lub zog siab tshaj plaws, thiab lub sijhawm luv luv ntawm ultrafast lasers yuav tsum tau tswj hwm kom zoo hauv koj lub cev. Feem ntau, ib qho ntawm cov kev daws teeb meem yooj yim tshaj plaws rau cov teeb meem no yog qhov dav spectrum tso zis ntawm lasers. Yog tias koj tau siv cov pulse ntev dua lossis cov lasers txuas ntxiv mus tas li yav dhau los, koj cov khoom siv kho qhov muag uas twb muaj lawm yuav tsis tuaj yeem cuam tshuam lossis xa cov bandwidth tag nrho ntawm ultrafast pulses.

Qhov ntsuas kev puas tsuaj ntawm laser
Ultrafast optics kuj muaj qhov sib txawv thiab nyuaj dua rau kev taug kev laser puas tsuaj thresholds (LDT) piv rau cov chaw laser ib txwm muaj. Thaum optics tau muab raucov lasers pulsed nanosecond, LDT tus nqi feem ntau yog nyob rau hauv qhov kev txiav txim ntawm 5-10 J / cm2. Rau ultrafast optics, cov nqi ntawm qhov loj no yog qhov tsis tau hnov ​​​​dua, vim tias LDT tus nqi yuav nyob rau ntawm qhov kev txiav txim ntawm <1 J / cm2, feem ntau ze rau 0.3 J / cm2. Qhov sib txawv tseem ceeb ntawm LDT amplitude nyob rau hauv ntau lub sijhawm pulse yog qhov tshwm sim ntawm laser puas tsuaj mechanism raws li lub sijhawm pulse. Rau nanosecond lasers lossis ntev duacov lasers pulsed, lub tshuab tseem ceeb uas ua rau puas tsuaj yog cua sov thermal. Cov txheej thiab cov ntaub ntawv substrate ntawmcov khoom siv kho qhov muagnqus cov photons uas tshwm sim thiab ua kom lawv sov. Qhov no tuaj yeem ua rau muaj kev cuam tshuam ntawm cov khoom siv lead ua ke. Kev nthuav dav thermal, kev tawg, yaj thiab kev ntxhov siab ntawm lattice yog cov txheej txheem puas tsuaj thermal ntawm cov nocov chaw laser.

Txawm li cas los xij, rau cov lasers ultrafast, lub sijhawm pulse nws tus kheej yog sai dua li lub sijhawm ntawm kev hloov pauv cua sov los ntawm lub laser mus rau cov khoom siv lattice, yog li qhov cuam tshuam thermal tsis yog qhov ua rau muaj kev puas tsuaj los ntawm laser. Hloov chaw, lub zog siab tshaj plaws ntawm lub laser ultrafast hloov pauv lub tshuab puas tsuaj mus rau hauv cov txheej txheem nonlinear xws li kev nqus ntau photon thiab ionization. Qhov no yog vim li cas nws tsis yooj yim sua kom nqaim qhov ntsuas LDT ntawm lub nanosecond pulse mus rau qhov ntawm lub ultrafast pulse, vim tias lub cev ntawm kev puas tsuaj yog txawv. Yog li ntawd, nyob rau hauv tib qho xwm txheej ntawm kev siv (piv txwv li, wavelength, lub sijhawm pulse, thiab rov ua dua), lub cuab yeej optical nrog qhov ntsuas LDT siab txaus yuav yog lub cuab yeej optical zoo tshaj plaws rau koj daim ntawv thov tshwj xeeb. Cov khoom siv optics kuaj nyob rau hauv ntau yam xwm txheej tsis sawv cev rau qhov kev ua tau zoo tiag tiag ntawm tib lub optics hauv lub kaw lus.

Daim Duab 1: Cov txheej txheem ntawm kev puas tsuaj los ntawm laser nrog lub sijhawm sib txawv