Chidule cha ma pulsed lasers

Chidule chalasers pulsed

Njira yolunjika kwambiri yopangiralaserpulses ndi kuwonjezera modulator kunja kwa laser mosalekeza. Njirayi imatha kupanga picosecond pulse yothamanga kwambiri, ngakhale yosavuta, koma kuwononga mphamvu yamagetsi ndi mphamvu yapamwamba sikungapitirire mphamvu yowunikira. Chifukwa chake, njira yabwino kwambiri yopangira ma pulses a laser ndikusinthira pabowo la laser, kusunga mphamvu panthawi yopuma ya sitimayo ndikuimasula panthawi yake. Njira zinayi zodziwika bwino zomwe zimagwiritsidwa ntchito popanga ma pulse kudzera pakusintha kwa laser cavity ndikusintha kwapaintaneti, kusintha kwa Q (kusintha kotayika), kutulutsa mpweya, ndi kutseka mode.

Kusintha kwa phindu kumapanga ma pulse amfupi posinthira mphamvu ya mpope. Mwachitsanzo, ma semiconductor gain-switched lasers amatha kupanga ma pulse kuchokera ku nanoseconds pang'ono kufika pa picoseconds zana posinthira pano. Ngakhale kuti mphamvu ya pulse ndi yochepa, njirayi ndi yosinthika kwambiri, monga kupereka kubwerezabwereza kosinthika komanso kugunda kwamtima. Mu 2018, ofufuza ku Yunivesite ya Tokyo adanenanso za laser ya femtosecond yosinthira semiconductor, yomwe ikuyimira kupambana kwaukadaulo wazaka 40.

Ma pulse amphamvu a nanosecond nthawi zambiri amapangidwa ndi ma lasers osinthika a Q, omwe amatulutsidwa maulendo angapo ozungulira pabowo, ndipo mphamvu ya pulse ili m'millijoules angapo mpaka ma joules angapo, kutengera kukula kwa dongosolo. Mphamvu zapakatikati (nthawi zambiri pansi pa 1 μJ) picosecond ndi femtosecond pulses amapangidwa makamaka ndi ma laser otsekeka. Pali ma pulses a ultrashort amodzi kapena angapo mu laser resonator yomwe imazungulira mosalekeza. Intracavity pulse iliyonse imatumiza kugunda kudzera pagalasi lolumikizana, ndipo kubwereza kumakhala pakati pa 10 MHz ndi 100 GHz. Chithunzi chomwe chili pansipa chikuwonetsa kufalikira kwabwinobwino (ANDi) kutulutsa soliton femtosecondchipangizo cha fiber laser, zambiri zomwe zimatha kumangidwa pogwiritsa ntchito zida za Thorlabs (fiber, lens, phiri ndi tebulo losamuka).

Njira yochotsera ma cavity ingagwiritsidwe ntchitoQ-kusintha laserskuti mupeze ma pulses afupikitsa ndi ma laser otsekedwa ndi mode kuti muwonjezere mphamvu yakugunda ndi kutsika kocheperako.

Nthawi yolamulira ndi ma frequency domain pulses
Mawonekedwe amtundu wa kugunda ndi nthawi nthawi zambiri amakhala osavuta ndipo amatha kuwonetsedwa ndi ntchito za Gaussian ndi sech². Nthawi ya pulse (yomwe imadziwikanso kuti pulse width) imasonyezedwa kwambiri ndi theka la kutalika kwa msinkhu (FWHM) mtengo, ndiko kuti, m'lifupi mwake momwe mphamvu ya kuwala ili osachepera theka la mphamvu yapamwamba; Q-switched laser imapanga nanosecond pulses lalifupi kudzera
Ma laser otsekeka amatulutsa ma ultra-short pulses (USP) motsatana ndi makumi a picoseconds mpaka femtoseconds. Zipangizo zamagetsi zothamanga kwambiri zimatha kuyeza mpaka makumi a picoseconds, ndipo mapiko amfupi amatha kuyezedwa ndi matekinoloje owoneka bwino monga autocorrelators, FROG ndi SPIDER. Ngakhale ma nanosecond kapena ma pulse ataliatali sasintha m'lifupi mwake pamene akuyenda, ngakhale atayenda mtunda wautali, ma pulse amfupi amatha kukhudzidwa ndi zinthu zosiyanasiyana:

Kubalalitsidwa kungayambitse kugunda kwakukulu, koma kumatha kusinthidwanso ndi kubalalitsidwa kwina. Chithunzi chotsatirachi chikuwonetsa momwe Thorlabs femtosecond pulse compressor amalipira kubalalitsidwa kwa maikulosikopu.

Nonlinearity nthawi zambiri samakhudza mwachindunji kukula kwa pulse, koma imakulitsa bandwidth, kupangitsa kuti kugunda kukhale kosavuta kubalalitsidwa panthawi yofalitsa. Mtundu uliwonse wa fiber, kuphatikizapo mauthenga ena opindula omwe ali ndi malire ochepa, amatha kukhudza mawonekedwe a bandwidth kapena ultra-short pulse, ndipo kuchepa kwa bandwidth kungayambitse kufalikira kwa nthawi; Palinso zochitika pamene kugunda m'lifupi mwa kugunda mwamphamvu kugunda kumakhala kochepa pamene sipekitiramu imakhala yopapatiza.