Bayanin laser pulsed

Bayaninpulsed lasers

Hanya mafi kai tsaye don samarwaLaserbugun jini shine ƙara mai daidaitawa zuwa waje na ci gaba da Laser. Wannan hanyar na iya samar da bugun bugun picosecond mafi sauri, kodayake mai sauƙi, amma ɓata makamashin haske da ƙarfin kololuwa ba zai iya wuce ƙarfin haske mai ci gaba ba. Sabili da haka, hanya mafi inganci don samar da bugun jini na Laser shine a canza shi a cikin rami na Laser, adana makamashi a cikin lokacin jirgin ƙasa da kuma sake shi a kan lokaci. Hanyoyi guda huɗu na yau da kullun da ake amfani da su don samar da bugun jini ta hanyar ƙirar cavity na Laser sune samun canji, Q-canzawa (canjin asarar), zubar da rami, da kulle yanayin.

Canjin riba yana haifar da gajerun bugun jini ta hanyar daidaita ƙarfin famfo. Misali, na'urorin da aka canza na semiconductor na iya haifar da bugun jini daga ƴan nanoseconds zuwa picoseconds ɗari ta hanyar daidaitawa na yanzu. Kodayake makamashin bugun jini yana da ƙasa, wannan hanyar tana da sassauƙa sosai, kamar samar da mitar maimaitawa da faɗin bugun bugun jini. A cikin 2018, masu bincike a Jami'ar Tokyo sun ba da rahoton wani na'ura mai amfani da wutar lantarki na femtosecond, wanda ke wakiltar ci gaba a cikin ƙwaƙƙwaran fasaha na shekaru 40.

Ƙaƙƙarfan bugun nanosecond gabaɗaya ana haifar da laser Q-switched, waɗanda ake fitarwa a cikin tafiye-tafiye da yawa a cikin rami, kuma ƙarfin bugun jini yana cikin kewayon millijoules da yawa zuwa joules da yawa, dangane da girman tsarin. Matsakaicin makamashi (gaba ɗaya ƙasa da 1 μJ) picosecond da femtosecond bugun jini ana yin su ne ta hanyar leza masu kulle-kulle. Akwai guda ɗaya ko fiye ultrashort bugun jini a cikin Laser resonator cewa zagayowar ci gaba. Kowane bugun jini na intracavity yana watsa bugun bugun jini ta hanyar madubi mai haɗa kayan aiki, kuma maimaitawar gabaɗaya yana tsakanin 10 MHz da 100 GHz. Hoton da ke ƙasa yana nuna cikakkiyar tarwatsawa ta al'ada (ANDi) mai ɓarna soliton femtosecondfiber Laser na'urar, Mafi yawan abin da za a iya ginawa ta amfani da daidaitattun kayan aikin Thorlabs (fiber, lens, mount and displacement table).

Ana iya amfani da dabarar zubar da rami donQ-switched Laserdon samun guntu bugun jini da na'urori masu kulle yanayin don ƙara ƙarfin bugun jini tare da ƙarami.

Yankin lokaci da mitar yanki
Siffar madaidaiciyar bugun bugun jini tare da lokaci gabaɗaya mai sauƙi ne kuma ana iya bayyana ta ta ayyukan Gaussian da sech². Lokacin bugun bugun jini (wanda kuma aka sani da faɗin bugun jini) galibi ana bayyana shi da ƙimar rabin tsayin tsayi (FWHM), wato faɗin da ƙarfin gani ya kai rabin ƙarfin kololuwa; Laser Q-switched yana haifar da gajerun bugun jini na nanosecond
Laser masu kulle-kulle suna samar da ultra-short pulses (USP) a cikin tsari na dubun picoseconds zuwa femtoseconds. Na'urorin lantarki masu saurin gudu kawai na iya auna har zuwa dubun picoseconds, kuma guntun bugun jini za'a iya auna su kawai tare da fasahar gani zalla kamar autocorrelators, FROG da SPIDER. Duk da yake nanosecond ko tsayin bugun jini da kyar ke canza fadin bugun bugun su yayin da suke tafiya, ko da a nesa mai nisa, matsananciyar gajeriyar bugun jini na iya shafar abubuwa da dama:

Watsewa na iya haifar da babban faɗuwar bugun jini, amma ana iya sake matsawa tare da tarwatsewa akasin haka. Hoton da ke gaba yana nuna yadda Thorlabs femtosecond pulse compressor ke ramawa don tarwatsawar microscope.

Rashin layi gabaɗaya baya shafar faɗin bugun bugun jini kai tsaye, amma yana faɗaɗa bandwidth, yana sa bugun jini ya fi sauƙi ga tarwatsewa yayin yaduwa. Duk wani nau'i na fiber, ciki har da sauran kafofin watsa labaru na samun riba tare da iyakacin iyaka, na iya rinjayar siffar bandwidth ko ultra-short pulse, kuma raguwa a cikin bandwidth zai iya haifar da fadada cikin lokaci; Akwai kuma lokuta inda nisa bugun bugun jini na bugun jini mai karfi ya zama guntu lokacin da bakan ya zama kunkuntar.