Kev tsim txoj kev pom ntawm 66-femtosecondhom-xauv laser
Lub laser 66-femtosecond mode-locked no yog ib lub laser fiber linear cavity all-polarization-maintaining ytterbium-doped nrog lub non-reciprocal phase shifter. Nws ua tiav 147 MHz fundamental frequency mode-locking. Los ntawm kev kho qhov deb ntawm cov gratings, qhov dav spectral ntawm 39.8 nm thiab qhov dav pulse ntawm 66 fs tom qab external compression tau txais. Ntawm lub zog twj siab, qhov thib ob thiab thib peb harmonic mode-locking nrog repetition frequencies ntawm 294.1 MHz thiab 442.3 MHz tau txais.
Kev piav qhia txog txoj kev kho qhov muag:
Lub resonator muaj cov khoom siv kho qhov muag ntawm ob sab thiab cov fiber uas tswj polarization nyob hauv nruab nrab. Sab laug muaj daim iav total reflection (M1), lub phaj nthwv dej λ/8 (EWP), thiab lub Faraday rotator (FR). Kev sib xyaw ua ke ntawm EWP thiab FR tuaj yeem siv ua lub tshuab hloov theem tsis sib xws, muab kev cuam tshuam theem tsis sib xws, yog li txhim kho lub peev xwm pib tus kheej. Cov fiber muaj cov khoom siv sib xyaw ua ke ntawm wavelength division multiplexing - collimator (WDM-Collimator), 62 cm ytterbium-doped polarization-maintaining fiber (Yb401-PM, CORACTIVE), thiab lub tshuab fiber collimator (Col). Cov fiber ntau ntxiv raug pumped los ntawm ib hom 976 nm laser diode (LD) nrog lub zog siab tshaj plaws ntawm 1.4 W. Qhov chaw sab xis muaj ib lub phaj ib nrab nthwv dej (HWP), lub polarization beam splitter (PBS), ib khub grating (LightSmyth T-1000-1040-3212-94), thiab ib daim iav reflection tag nrho (M2). Cov khub grating kis nrog lub kab ceev ntawm 1000 kab / hli muab kev them nyiaj rau sab hauv-cavity dispersion. Qhov deb ntawm ob lub gratings tuaj yeem hloov kho los ntawm ib theem. Qhov ntev ntawm qhov chaw dawb los ntawm lub collimator mus rau ob daim iav reflection ntawm ob sab yog 5.5 cm thiab 6.5 cm feem. Lublasertso zis pulses hauv txoj kev linearly polarized los ntawm PBS.
Txoj cai ua haujlwm:
Lub zog pib normalized pulse uas xa los ntawm lub voj voog intracavity pib ntawm PBS thiab xa mus rau M1. Thaum pib, HWP yuav rhuav lub zog ua ob lub orthogonal, thiab tom qab ntawd nkag mus rau hauv cov fiber ntau uas khaws cia polarization thiab nthuav dav raws cov kab ceev thiab qeeb. Qhov sib piv ntawm cov zog ntawm cov pulses raws ob lub orthogonal axes yog txiav txim siab los ntawm lub kaum sab xis (θh) ntawm HWP. Thaum lub sijhawm nthuav dav hauv cov fiber ntau, vim muaj cov teebmeem nonlinear, qhov sib npaug ntawm cov orthogonal polarized pulses yuav ua rau muaj kev hloov pauv theem nonlinear uas cuam tshuam nrog lub zog. Daim iav kawg M1 ua rau cov pulses orthogonal hla dhau lub zog hloov pauv theem ob zaug thiab rov qab mus rau cov fiber ntau uas khaws cia polarization. Cov pulses orthogonal tau txais qhov hloov pauv theem π/2 tsis sib xws thiab pauv qhov kev nthuav dav optical axis. Qhov sib txawv ntawm pawg ceev ntawm cov pulses orthogonal polarized ua rau muaj kev them nyiaj rau qhov cuam tshuam. Thaum kawg, lub zog sib sau ua ke ntau yam kev hloov pauv theem nonlinear thiab raug cuam tshuam ntawm PBS. Ua ib lub polarizer, PBS tso cai rau cov pulses polarization xeev tsim nyog hla dhau, thaum tus so yog reflected tawm ntawm lub qhov. Cov txheej txheem no ua lub luag haujlwm ntawm lub absorber dag nyob rau hauv lub qhov kab no.laser kho qhov muag. Thaum qhov deb ntawm cov grating khub raug txo kom txog 3.2 hli, sab laug ntawm lub spectrum yuav ua rau ntxhab dua. Lub sijhawm no, qhov kev sib kis ntawm cov kab noj hniav yog qhov zoo, thiab lub zog siab tshaj plaws ntawm ib lub zog ntawm 3.57 nJ tau txais. Cov kab sib txuas ntawm lub zog ntawm lub zog tau los ntawm kev nias sab nraud ntawm lub zog nrog qhov dav tshaj plaws 39.8 nm spectral dav yog haum los ntawm Gaussian function, uas yog 66 fs.
Lub sijhawm tshaj tawm: Lub Ob Hlis-25-2026