Recently, the Russell Center for Advanced Lightwave Science of Hangzhou Institute of Optics and Fine Mechanics, the United Nations University of Science and Technology Hangzhou Institute for Advanced Studies, the Shanghai Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences, and Ifibo (Ningbo) Optoelectronics Technology Co., Ltd. published their latest research results Rahvusvahelises Top Optical Journalis "Optica" ja saavutas esimest korda vangitaseme, sadu femtosekundide, 2 . 8 μm riba keskmise sissetungiga impulssides õõnsusega fotoonilistes kristalls-pcf (holl-core pcf) esimest korda kõrge truuduse, ülitõhususe, ülitõhususe ja kõrge ühe režiimilise puhtuse painduvusega painduvalt painduvalt painduvalt painduvalt. See tulemus ei paku mitte ainult tõhusat lahendust keskmise infrapuna-ultrafastiliste impulsside puudustele edastamisel, vaid loob ka aluse keskmise infrapunarakenduse laiendamiseks
High-power mid-infrared ultrafast broadband light sources have important applications in advanced spectroscopy, material fine processing, medical surgery, and remote sensing. The limitations of laser transmission have hindered the further expansion of mid-infrared laser applications. In traditional transmission methods, the absorption of various gas molecules in the spatial optical path causes deformation of the output light spot and deterioration of pulse quality. Solid mid-infrared optical fiber has serious nonlinear accumulation, which causes serious distortion of the output time-frequency signal. To solve this problem, the research team used a self-made single-hole eight-ring structure Hollow-core PCF (length 5 m) to transmit mid-infrared ultrafast pulses. Thanks to the advantages of low transmission loss, low nonlinear effect accumulation and support for rapid vacuum extraction of Hollow-core PCF, the team not only solved the problems caused by traditional transmission methods, but also successfully achieved efficient transmission with an overall efficiency of >70%.
During the experiment, the experimenters used a self-built mid-infrared pulse fiber laser as the light source and a 5 m long Hollow-core PCF as the transmission medium. The two ends of the Hollow-core PCF were fixed in the air chamber so that the Hollow-core PCF could be evacuated using a vacuum pump. After the vacuum was drawn (the entire extraction process took less than 1 minute, and the gas pressure was drawn to ~10 mbar), the team successfully achieved an overall laser efficiency of > 70%, a Gaussian spot output that was close to the diffraction limit, and the entire system showed excellent stability. In addition, the spectral shape of the output in the frequency domain was basically consistent with the input. In the time domain, due to the small amount of waveguide dispersion of the hollow-core PCF (-2.04 fs2/mm @ 2.8 μm), the pulse width was widened from the input 117 fs to 404 fs. Subsequently, the experimenters added Ge and ZnSe positive dispersion materials to compensate for the negative dispersion introduced by the hollow-core PCF, coupling lens and air chamber window, and obtained an output with a pulse width of 98 fs (close to the transformation limit pulse width of 96 fs), with a peak power of 170 kW. In addition, the experimenters also used the autocorrelation trace to estimate that the output fundamental mode energy accounted for >95%.
Samuti võrdlesid eksperimenteerijad ülekandeskeemi sama pikkusega ruumilise optilise teega ja tahketuumaga fluoriidikiudu . tulemused näitavad, et ultrafastiliste impulsside edastamise ajal tahkete fluoriidi kiududes on mittelineaarne efekt liiga tugev, mille tulemuseks on tuulevaiksed ja mis on tugistavast fikseerinud, mis on tugi- ja sümboliseerivaks. fibers in the transmission of high-peak power mid-infrared ultrafast pulses. The experiment achieved high-efficiency, high-fidelity and high-single-mode purity mid-infrared laser flexible transmission technology, laying a good foundation for the application of broadband mid-infrared ultrafast light sources in spectroscopy, infrared countermeasures and remote sensing.
Asjakohased uurimistulemused avaldati Optica Lasers and Optoelectronics Top Journalis pealkirjaga "Lairiba paindlik kohaletoimetamine, 100 FS-i infrapuna-impulsi vesi-absorptsioonribas, kasutades õõnestuumalisi fotoonilisi kristallkiudu". {4} {4} Lin Wei, mis on Wourn of Wosyh of Advancy ja Fine'i instituut. Tehnoloogia ja Shanghai optika ja peene mehaanika instituudi doktoriõpilane Li Zeqing on esimesed autorid ning Huang Jiapeng, Jiang Xin ja Russelli keskuse Pang Meng on kaasrežiimis autorid .}
Joonis 1. eksperimentaalne seadistamine ja tulemused . (a) Eksperimentaalne optiline tee . objektiiv, kaetud kohvikut Plano-Convex objektiiv; HWP, poollaine plaat; QWP, veerandlaine plaat; Fm, painutatud peegel; FTIR, Fourier teisenduse infrapunaspektromeeter; AC, Autokorrelaator . (b) kiudstruktuuri SEM-pilt . (c) Kärbimismeetodi abil mõõdetud kadusspektri abil tähistab varjutatud ala mõõtmismäär (oranž, vasak telg) ja arvutatud dispersioonkõver (sinine, parem telg) {{{{} ({{} (d) (d) (d) ({{{}. Õõnestuumaga PCF . (E), kasutades 30 mM Znse ja 5 mm GE materjale, saavutati impulsi väljund, mille peaaegu transformatsiooniga piiratud impulsi laius oli 98 Fs {.
Joonis 2. erinevate ülekanderežiimide võrdlus . (a) Veeauru . (b) otsese laserväljundi (hall) ja jõuülekandespektri normaliseeritud neeldumisspektri normaliseeritud neeldumisspektri ja ruumilise pcf-i levitamisspektri ülekandespektris asuvas ruumilises optilisel teel (libliks), mis on õhkkere ja edastusspektr. (punane) . Parempoolne külg näitab laienenud spektrit vahemikus 2.7-2.8 μm .} (c) Ramani solitoni genereerimine tahkes sisalduvas fluoriidi kiudul. ftiir-spektr on vasakul ja 10} -l {{{{{{{{{{{{{{{{{{{{{{
