Lub compact thiab robust tag nrho-khoom-state mid-infrared (MIR) laser ntawm 6.45 um nrog siab nruab nrab tso zis hwj chim thiab ze-Gaussian beam zoo yog qhia.A siab tshaj plaws tso zis zog ntawm 1.53 W nrog ib tug mem tes dav ntawm kwv yees li 42 ns ntawm 10 kHz yog ua tiav siv ZnGeP2 (ZGP) optical parametric oscillator (OPO) .Qhov no yog lub zog nruab nrab siab tshaj plaws ntawm 6.45 um ntawm txhua lub zog-lub xeev laser rau qhov zoo tshaj plaws ntawm peb txoj kev paub.Qhov nruab nrab beam zoo tshaj plaws yog ntsuas los ntawm M2 = 1.19.
Ntxiv mus, lub zog tso zis siab ruaj khov tau lees paub, nrog lub zog hloov pauv tsawg dua 1.35% rms tshaj 2 h, thiab lub laser tuaj yeem ua haujlwm tau zoo rau ntau tshaj 500 h hauv tag nrho.Siv qhov no 6.45 um mem tes ua hluav taws xob, ablation ntawm tsiaj Cov ntaub so ntswg ntawm lub hlwb raug kuaj. Tsis tas li ntawd, cov txiaj ntsig kev puas tsuaj yog kev tshawb fawb thawj zaug, rau qhov zoo tshaj plaws ntawm peb cov kev paub, thiab cov txiaj ntsig tau qhia tias qhov MIR laser no muaj peev xwm ablation zoo, ua rau nws muaj peev xwm hloov pauv dawb electron lasers.© 2022 Optica Publishing Group

https://doi.org/10.1364/OL.446336

Mid-infrared (MIR) 6.45 um laser hluav taws xob muaj peev xwm siv-cations hauv high-precision tshuaj teb vim nws qhov zoo ntawm tus nqi ablation ntau thiab kev puas tsuaj tsawg 【1】.Free electron lasers (FELs), strontium vapor lasers, roj Raman lasers, thiab solid-state lasers raws li ib tug optical paramet-ric oscillator (OPO) los yog txawv zaus tiam (DFG) yog feem ntau siv 6.45 um laser qhov chaw.Txawm li cas los, tus nqi siab, loj loj, thiab complex qauv ntawm FELs txwv lawv. daim ntawv thov.Strontium vapor lasers thiab roj Raman lasers tuaj yeem tau txais lub hom phiaj band, tab sis ob qho tib si muaj kev ruaj ntseg tsis zoo, luv ser-
Lwm lub neej, thiab xav tau kev saib xyuas nyuaj. Cov kev tshawb fawb pom tias 6.45 um solid-state lasers tsim ib qho me me thermal dam-hnub nyoog ntau yam hauv cov ntaub so ntswg lom thiab tias lawv qhov tob tob tob dua li cov FEL nyob rau hauv tib yam mob, uas tau txheeb xyuas tias lawv muaj peev xwm. siv los ua lwm txoj hauv kev zoo rau FELs rau cov ntaub so ntswg ablation 【2】 . Tsis tas li ntawd, cov khoom siv lub xeev lasers muaj qhov zoo ntawm cov qauv compact, zoo stability, thiab

tabletop lag luam, ua rau lawv cov cuab yeej cog lus kom tau txais a6.45μn lub teeb ci.Raws li paub zoo, nonlinear infrared crystals ua lub luag haujlwm tseem ceeb hauv cov txheej txheem hloov pauv zaus siv los ua kom muaj kev ua tau zoo MIR lasers.Piv rau oxide infrared quaj-tals nrog 4 um txiav tawm ntug, cov khoom siv tsis muaj oxide zoo. haum rau tsim MIR lasers.Cov muaju muaj xws li feem ntau ntawm cov chalcogenides, xws li AgGaS2 (AGS) 【3,41, LiInS2 (LIS)】 5,61, LilnSe2 (LISe) 【7】, BaGaS (BGS) 8,9 】, thiab BaGaSe (BGSe) 【10-12】, nrog rau cov phosphorus compounds CdSiP2 (CSP) 【13-16】 thiab ZnGeP2 (ZGP) 【17】; ob qho tib si tom qab ob leeg muaj rela-tively loj nonlinear coefficients. Piv txwv li, MIR hluav taws xob tuaj yeem tau txais los ntawm CSP-OPOs.Txawm li cas los xij, feem ntau CSP-OPOs ua haujlwm ntawm ultrashort (pico-thiab femtosecond) lub sij hawm teev thiab yog synchronously pumped los ntawm kwv yees li 1 um hom-xauv lasers. Hmoov tsis zoo, cov synchronously pumped OPO ( SPOPO) cov txheej txheem muaj kev teeb tsa nyuaj thiab raug nqi kim.Lawv lub zog nruab nrab kuj tseem qis dua 100 mW ntawm ib puag ncig 6.45 um 【13-16】.Piv nrog CSP siv lead ua, ZGP muaj ntau dua laser puas threshold (60 MW / cm2), siab dua thermal conductiv-ity (0.36 W / cm K), thiab qhov sib piv nonlinear coefficient (75pm / V). Kev siv hluav taws xob 【18-221.Piv txwv li, lub tiaj tus kab noj hniav ZGP-OPO nrog kev sib tw ntawm 3.8-12.4 um pumped los ntawm 2.93 um laser tau pom.Qhov siab tshaj plaws ib leeg-mem tes zog ntawm lub teeb idler ntawm 6.6 um yog 1.2 mJ 【201.Rau qhov tshwj xeeb wavelength ntawm 6.45 um, lub zog maxi-mum ib leeg-maj zog ntawm 5.67 mJ ntawm qhov rov ua dua ntawm 100 Hz tau ua tiav siv lub nplhaib tsis-planar OPO kab noj hniav raws li ZGP siv lead ua. zaus ntawm 200Hz, qhov nruab nrab tso zis zog ntawm 0.95 W tau mus txog 【221.Raws li peb tau paub, qhov no yog lub siab tshaj plaws tso zis zog ua tiav ntawm 6.45 um.Cov kev tshawb fawb uas twb muaj lawm qhia tias lub zog nruab nrab siab dua yog qhov tsim nyog rau cov ntaub so ntswg zoo ablation 【23】.Yog li ntawd, kev txhim kho ntawm lub zog siv hluav taws xob 6.45 um laser yuav yog qhov tseem ceeb hauv kev txhawb nqa cov tshuaj lom neeg.Nyob rau hauv tsab ntawv no, peb tshaj tawm ib qho yooj yim, compact tag nrho cov khoom-lub xeev MIR 6.45 um laser uas muaj ib tug siab nruab nrab tso zis zog thiab yog raws li ib tug ZGP-OPO pumped los ntawm ib tug nanosecond (ns)-mem tes 2.09 um.

laser.Qhov siab tshaj plaws nruab nrab tso zis hwj chim ntawm 6.45 um laser yog mus txog 1.53 W nrog ib tug mem tes dav ntawm kwv yees li 42ns ntawm ib tug repetition zaus ntawm 10 kHz, thiab nws muaj zoo heev beam zoo.Qhov ablating nyhuv ntawm 6.45 um laser ntawm cov ntaub so ntswg tsiaj yog soj ntsuam.Qhov kev ua hauj lwm no qhia tau hais tias lub laser yog ib tug zoo mus kom ze rau tiag tiag tissuc ablation, raws li nws ua raws li ib tug laser scalpel.Qhov kev sim teeb tsa yog sketched nyob rau hauv Fig.1.ZGP-OPO yog pumped los ntawm lub tsev LD-pumped 2.09 um Ho:YAG laser uas xa 28 W ntawm nruab nrab lub zog ntawm 10 kHz.with ib tug mem tes ntev ntawm kwv yees li 102 ns ( FWHM) thiab qhov nruab nrab beam zoo tshaj plaws M2 ntawm kwv yees li 1.7.MI thiab M2 yog ob 45 daim iav nrog cov txheej uas muaj kev cuam tshuam zoo heev ntawm 2.09 um.Cov iav no pab tswj kev tswj ntawm lub twj tso kua mis beam.Ob lub tsom iav tsom iav (f1 = 100mm , f2 = 100 mm) yog siv rau beam collimation nrog ib tug beam txoj kab uas hla ntawm 3.5 hli nyob rau hauv lub ZGP crystal.Ib optical isolator (ISO) yog siv los tiv thaiv lub twj tso kua mis beam rov qab mus rau lub 2.09 um twj tso kua mis qhov chaw.A ib nrab-yoj phaj (HWP) ntawm 2.09 um yog siv los tswj lub polarization ntawm lub teeb lub teeb.M3 thiab M4 yog OPO kab noj hniav iav, nrog ca CaF2 siv los ua cov khoom siv substrate.Cov iav pem hauv ntej M3 yog anti-reflection coated (98%) rau lub twj tso kua mis beam thiab high-reflection coated (98%) rau 6.45 um idler thiab 3.09 um teeb liab nthwv dej.Qhov tawm-muab daim iav M4 yog heev reflective (98%) ntawm 2.09um thiab 3.09 um thiab tso cai ib feem kis ntawm 6.45 um idler.ZGP siv lead ua yog txiav ntawm 6-77.6 ° andp = 45 ° rau hom-JⅡ theem sib txuam 【2090.0 （o）6450.0 （o） + 3091.9 （e）】, uas yog tsim nyog rau ib lub wavelength tshwj xeeb thiab yields parametric teeb nrog ib tug nqaim. linewidth piv nrog hom-I theem txuam.Qhov qhov ntev ntawm ZGP siv lead ua yog 5 hli x 6 hli x 25 hli, thiab nws yog polished thiab anti-reflection coated ntawm ob qhov kawg facets rau saum peb nthwv dej.Nws yog qhwv hauv indium ntawv ci thiab tsau nyob rau hauv ib tug tooj liab kub dab dej nrog dej txias (T = 16).Lub kab noj hniav ntev yog 27 hli.Lub sij hawm mus ncig teb chaws ntawm OPO yog 0.537 ns rau lub twj tso kua mis laser.Peb kuaj qhov kev puas tsuaj pib ntawm ZGP siv lead ua los ntawm R -on-I txoj kev 【17】.Qhov kev puas tsuaj ntawm ZGP siv lead ua tau ntsuas yog 0.11 J / cm2 ntawm 10 kHz.in qhov kev sim, coj mus rau lub ncov zog ceev ntawm 1.4 MW / cm2, uas yog tsawg vim qhov kuj tsis zoo txheej zoo.Lub zog tso zis ntawm lub teeb hluav taws xob tsim hluav taws xob yog ntsuas los ntawm lub ntsuas hluav taws xob (D, OPHIR, 1 uW txog 3 W), thiab lub wavelength ntawm lub teeb liab lub teeb raug saib xyuas los ntawm spectrometer (APE, 1.5-6.3 m). tau txais lub zog tso zis siab ntawm 6.45 um, peb opti-mize tus qauv tsim ntawm qhov tsis sib xws ntawm OPO.A cov lej simulation yog ua los ntawm peb-yoj sib xyaw txoj kev xav thiab paraxial propagation cquations 【24,25】; hauv kev simulation, peb ntiav cov tsis sib xws rau qhov kev sim thiab xav tias muaj cov khoom siv mem tes nrog Gaussian profile hauv qhov chaw thiab lub sijhawm.Qhov kev sib raug zoo ntawm OPO tso zis iav

transmittance, twj tso kua mis siv zog, thiab tso zis efficiency yog optimized los ntawm manipulating lub twj tso kua mis beam ceev nyob rau hauv cov kab noj hniav kom ua tau siab zog tso zis ntau zog thaum ib txhij zam kev puas tsuaj rau lub ZGP siv lead ua thiab cov khoom siv kho qhov muag. Yog li, lub zog twj tso kua mis siab tshaj plaws yog txwv rau 20. W rau ZGP-OPO kev ua haujlwm.Simulated cov txiaj ntsig qhia tau hais tias thaum lub sijhawm ua haujlwm zoo tshaj plaws nrog kev xa tawm ntawm 50% yog siv, qhov siab tshaj plaws lub zog ceev tsuas yog 2.6 x 10 W / cm2 hauv ZGP crys-tal, thiab qhov nruab nrab cov zis hluav taws xob ntawm ntau tshaj 1.5 W tuaj yeem tau txais.Daim duab 2 qhia txog kev sib raug zoo ntawm kev ntsuas cov zis hluav taws xob ntawm idler ntawm 6.45 um thiab qhov xwm txheej twj tso kua mis fais fab.Nws tuaj yeem pom los ntawm Fig.2 tias cov zis hluav taws xob ntawm idler nce monotonously nrog rau Qhov teeb meem twj tso kua mis zog.Lub twj tso kua mis pib sib haum mus rau qhov nruab nrab twj tso kua mis lub zog ntawm 3.55WA siab tshaj plaws idler tso zis zog ntawm 1.53 W yog ua tiav ntawm lub twj tso kua mis lub zog ntawm kwv yees li 18.7 W, uas sib raug rau qhov kev hloov kho qhov muag-rau-kho qhov muag of kwv yees li 8.20%% thiab quantum conversion cfliciency ntawm 25.31%.Rau kev nyab xeeb mus sij hawm ntev, lub laser yog ua nyob ze rau 70% ntawm nws siab tshaj tawm-tso fais fab.Lub zog stability yog ntsuas ntawm ib tug tso zis zog ntawm IW, raws li qhia nyob rau hauv inset (a) nyob rau hauv Fig.2.Nws tau pom tias qhov ntsuas lub zog hloov pauv tsawg dua 1.35% rms hauv 2 h, thiab lub laser tuaj yeem ua haujlwm tau zoo rau ntau tshaj 500 h hauv tag nrho.Qhov wavelength ntawm lub teeb liab nthwv dej yog ntsuas es tsis txhob ntawm tus idler vim qhov txwv wavelength ntau ntawm lub spectrometer (APE, 1.5-6.3 um) siv nyob rau hauv peb cov kev sim.Qhov ntsuas lub teeb liab wavelength yog nruab nrab ntawm 3.09 um thiab kab dav yog kwv yees li 0.3 nm, raws li qhia. nyob rau hauv inset (b) ntawm Fig.2.Lub nruab nrab wavelength ntawm lub idler yog ces deduced yuav 6.45um.Lub mem tes dav ntawm lub idler yog kuaj pom los ntawm ib tug photodetector (Thorlabs, PDAVJ10) thiab kaw los ntawm ib tug digital oscilloscope (Tcktronix, 2GHz. ).Ib yam oscilloscope waveform yog qhia nyob rau hauv Fig.3 thiab qhia ib tug mem tes dav ntawm kwv yees li 42 ns.The mem tes davyog 41.18% nqaim rau 6.45 um idler piv rau 2.09 um twj pulse vim qhov nce ntawm lub cev nce nqaim ntawm cov txheej txheem hloov pauv zaus uas tsis yog-linear.Vim li ntawd, qhov sib thooj idler mem tes ncov lub zog yog 3.56kW.Cov nqaj zoo ntawm cov 6.45 um idler yog ntsuas nrog lub laser beam

analyzer (Spiricon, M2-200-PIII) ntawm 1 W ntawm lub zog tso zis, raws li qhia hauv daim duab.4.Qhov ntsuas qhov tseem ceeb ntawm M2 thiab M, 2 yog 1.32 thiab 1.06 raws x axis thiab y axis, raws li, sib xws rau qhov nruab nrab beam zoo qhov tseem ceeb ntawm M2 = 1.19.Qhov insct ntawm Fig.4 qhia tau hais tias ob-dimensional (2D) beam siv profile, uas muaj ze-Gaussian spatial hom.Los xyuas kom meej tias 6.45 um mem tes muab abla-tion zoo, Ib qho pov thawj-ntawm-txoj cai kev sim nrog laser ablation ntawm porcine hlwb yog nqa tawm.Ib f = 50 lo ntsiab muag yog ua hauj lwm los tsom lub 6.45 um mem tes beam mus rau ib lub duav vojvoog ntawm txog 0.75 mm.Qhov txoj hauj lwm yuav tsum tau ablated ntawm porcine hlwb ntaub so ntswg. yog muab tso rau ntawm lub ntsej muag ntawm lub laser beam.Qhov kub ntawm qhov chaw (T) ntawm cov ntaub so ntswg lom raws li kev ua haujlwm ntawm qhov chaw radial r yog ntsuas los ntawm lub thermocamera (FLIR A615) synchronously thaum lub sij hawm ablation txheej txheem.Cov irradiation ntev yog 1 , 2,4,6,10, thiab 20 s ntawm lub zog laser ntawm I W.Rau txhua lub sijhawm irradiation, rau cov qauv ua haujlwm yog blated: r = 0,0.62,0.703,1.91,3.05, thiab 4.14 hli raws radial kev taw qhia nrog rau qhov chaw nruab nrab ntawm irradiation txoj hauj lwm, raws li qhia nyob rau hauv Fig.5.Cov squares yog cov ntsuas kub cov ntaub ntawv.Nws yog pom nyob rau hauv Fig.5 hais tias qhov kub thiab txias. ntawm ablation txoj hauj lwm ntawm cov ntaub so ntswg nce nrog nce irradiation duration.Qhov siab tshaj plaws tem-peratures T ntawm qhov chaw taw tes r = 0 yog 132.39,160.32,196.34,

205.57,206.95, thiab 226.05C rau irradiation ntev ntawm 1,2,4,6,10, thiab 20 s, ntsig txog.To soj ntsuam cov khoom puas tsuaj, qhov kub thiab txias faib rau ntawm ablated ntaub so ntswg nto yog simulated.Qhov no yog nqa tawm raws li Lub thermal conduction txoj kev xav rau cov ntaub so ntswg lom 126 】 thiab txoj kev xav ntawm laser propagation nyob rau hauv cov ntaub so ntswg lom 【27】 ua ke nrog cov optical tsis ntawm porcine hlwb 1281.
Kev simulation yog ua nrog qhov kev xav ntawm ib qho kev tawm tswv yim Gaussian beam.Vim tias cov ntaub so ntswg lom siv nyob rau hauv cov exper-iment yog cais cov porcine hlwb cov ntaub so ntswg, lub zog ntawm cov ntshav thiab cov metabolism hauv qhov kub thiab txias yog ignored, thiab cov porcine hlwb cov ntaub so ntswg yog simplified rau hauv lub hlwb. Cov duab ntawm lub tog raj kheej rau simula-tion.Cov tsis siv nyob rau hauv lub simulation yog summarized nyob rau hauv Table 1.Cov khoom curves qhia nyob rau hauv Fig.5 yog cov simulated radial kub distributions nrog rau kev hwm rau lub ablation chaw ntawm cov ntaub so ntswg nto rau rau qhov sib txawv irradiation. durations.Lawv nthuav tawm Gaussian kub profile los ntawm qhov chaw mus rau lub periphery.Nws yog pov thawj los ntawm Fig.5 tias cov ntaub ntawv sim agrce zoo nrog cov simulated tau.Nws kuj yog pom tseeb los ntawm Fig.5 tias qhov simulated kub ntawm qhov chaw ntawm lub ablation txoj hauj lwm nce raws li lub sij hawm irradia-tion nce rau txhua irradiation.Kev tshawb fawb yav dhau los tau pom tias cov hlwb hauv cov ntaub so ntswg zoo kawg nkaus nyob rau hauv tem-peratures hauv qab no.55C, uas txhais tau hais tias cov hlwb tseem ua haujlwm nyob rau hauv thaj chaw ntsuab (T <55C) ntawm cov nkhaus hauv daim duab 5.Cov kab daj ntawm txhua qhov nkhaus (55C)60C) .Nws tuaj yeem pom hauv daim duab 5 uas simulated ablation radii ntawm T = 60 ° Care0.774,0.873,0.993,1.071,1.198 thiab 1.364 mm, ntsig txog, rau irradiation ntev ntawm 1,2,4,6, 10, thiab 20s, thaum lub simulated ablation radii ntawm T = 55C yog 0.805,0.908,1.037,1.134,1.271, thiab 1.456 mm, raws li quantitatively soj ntsuam cov ablation nyhuv, lub arca yuav 1 8 hlwb tuag. 2.394,3.098,3.604,4.509, thiab 5.845 mm2 rau 1,2,4,6,10, thiab 20s ntawm irradiation, ntsig txog.Lub cheeb tsam nrog kev puas tsuaj cheeb tsam pom muaj 0.003,0.0040.006,0.013 thiab 0.027 mm2.Nws tuaj yeem pom tau tias cov cheeb tsam laser ablation thiab thaj chaw puas tsuaj nce ntxiv nrog rau lub sijhawm irradiation.Peb txhais tau tias qhov kev puas tsuaj puas ntsoog yog qhov piv ntawm thaj tsam kev puas tsuaj ntawm 55C s T60C.Qhov kev puas tsuaj ntawm cov khoom pov tseg yog pom. los yog 8.17%, 8.18%, 9.06%, 12.11%, 12.56%, thiab 13.94% rau lub sijhawm sib txawv irradiation, uas txhais tau hais tias qhov kev puas tsuaj ntawm cov ntaub so ntswg ablated me me. Yog li ntawd, kev sim ua tiavl cov ntaub ntawv thiab cov txiaj ntsig simulation qhia tau hais tias qhov kev cog lus loj, lub zog siab, tag nrho cov khoom-lub xeev 6.45 um ZGP-OPO laser muab kev ua haujlwm zoo ntawm cov ntaub so ntswg lom. MIR pulsed 6.45 um laser qhov chaw raws li ib tug ns ZGP-OPO mus kom ze.A siab tshaj plaws nruab nrab hwj chim ntawm 1.53 W tau nrog lub ncov zog ntawm 3.65kW thiab ib tug nruab nrab beam zoo yam ntawm M2 = 1.19.Sing no 6.45 um MIR hluav taws xob, a Cov ntaub ntawv pov thawj-ntawm-txoj cai kev sim ntawm lub laser ablation ntawm cov ntaub so ntswg tau ua.Qhov kub ntawm qhov chaw ntawm cov ntaub so ntswg ablated tau sim ntsuas thiab theoretically simu-lated.Cov ntaub ntawv ntsuas tau pom zoo nrog cov txiaj ntsig simulated. Tsis tas li ntawd, qhov kev puas tsuaj puas tsuaj tau soj ntsuam theoretically. thawj zaug.Cov txiaj ntsig no tau lees paub tias peb cov ntsiav tshuaj MIR mem tes laser ntawm 6.45 um muab cov txiaj ntsig zoo ntawm cov nqaij mos thiab muaj peev xwm ua tau zoo los ua cov cuab yeej siv hauv kev kho mob thiab kev tshawb fawb lom neeg, vim nws tuaj yeem hloov pauv FEL loj heev.ib tug laser scalpel.