ʻenehana laser laulaʻi haiki Mahele ʻEkahi

I kēia lā, e hoʻolauna mākou i kahi laser "monochromatic" i ka laser laina ākea ākea.ʻO kona puka ʻana e hoʻopiha i nā āpau i nā ʻano noiʻi he nui o ka laser, a i nā makahiki i hala iho nei ua hoʻohana nui ʻia i ka ʻike hawewe gravitational, liDAR, puʻupuʻu sensing, kiʻekiʻe-wikiwiki coherent optical kamaʻilio a me nā māla ʻē aʻe, he "misiona" hiki ʻole ke hoʻopau wale ʻia ma ka hoʻomaikaʻi ʻana i ka mana laser.

He aha ka laser laina laina haiki?

ʻO ka huaʻōlelo "ākea laina" e pili ana i ka laulā laina kikoʻī o ka laser i ka domain frequency, ka mea maʻamau i helu ʻia ma nā huaʻōlelo o ka hapalua-peak piha ākea o ka spectrum (FWHM).Hoʻopili nui ʻia ka linewidth e ka radiation spontaneous o nā atom hauʻoli a i ʻole nā ​​​​iona, ka walaʻau ʻana, ka haʻalulu mechanical o ka resonator, ka jitter wela a me nā mea ʻē aʻe o waho.ʻO ka liʻiliʻi o ka waiwai o ka laulā laina, ʻoi aku ka kiʻekiʻe o ka maʻemaʻe o ka spectrum, ʻo ia hoʻi, ʻoi aku ka maikaʻi o ka monochromaticity o ka laser.ʻO nā lasers me ia mau hiʻohiʻona he liʻiliʻi liʻiliʻi ka leo a i ʻole ka leo alapine a me ka liʻiliʻi liʻiliʻi o ka leo.I ka manawa like, ʻoi aku ka liʻiliʻi o ka waiwai laula laina o ka laser, ʻoi aku ka ikaika o ka coherence pili, i hōʻike ʻia ma ke ʻano he lōʻihi lōʻihi loa.

ʻO ka ʻike a me ka hoʻohana ʻana i ka laser linewidth haiki

Ua kaupalena ʻia e ka loaʻa ʻana o ka laina laina o ka mea hana o ka laser, ʻaneʻane hiki ʻole ke hoʻomaopopo pololei i ka hoʻopuka ʻana o ka laser linewidth haiki ma ka hilinaʻi ʻana i ka oscillator kuʻuna.I mea e ʻike ai i ka hana o ka laser linewidth haiki, pono e hoʻohana i nā kānana, grating a me nā mea hana ʻē aʻe e kaupalena a koho paha i ka modulus longitudinal i ka spectrum loaʻa, e hoʻonui i ka ʻokoʻa loaʻa ʻupena ma waena o nā mode longitudinal. liʻiliʻi a i ʻole hoʻokahi wale nō oscillation mode longitudinal i ka resonator laser.Ma kēia kaʻina hana, pono pinepine e hoʻomalu i ka mana o ka walaʻau ma ka hopena laser, a e hōʻemi i ka hoʻonui ʻana o nā laina spectral i hoʻokumu ʻia e ka vibration a me nā hoʻololi o ka mahana o ke kaiapuni waho;I ka manawa like, hiki ke hoʻohui pū ʻia me ka nānā ʻana o ka pae a i ʻole ka nui o ka noise spectral density e hoʻomaopopo i ke kumu o ka walaʻau a hoʻopaʻa i ka hoʻolālā ʻana o ka laser, i mea e hoʻokō ai i ka hopena paʻa o ka laser linewidth haiki.

E nānā kākou i ka hoʻokō ʻana i ka hana linewidth haiki o nā ʻano like ʻole o nā lasers.

(1)Laser semiconductor

Loaʻa i nā lasers Semiconductor nā mea maikaʻi o ka nui compact, kiʻekiʻe kiʻekiʻe, ola lōʻihi a me nā pono waiwai.

ʻO ka Fabry-Perot (FP) optical resonator i hoʻohana ʻia i ka wā kahikonā laser semiconductor'oscillates ma'amau i ka multi-longitudinal mode, a me ka laula laina pukana mea akea, no laila, pono e hoonui i ka optical manaʻo e loaa ka puka o ka haiki laina laula.

ʻO nā manaʻo manaʻo i hāʻawi ʻia (DFB) a me Distributed Bragg reflection (DBR) ʻelua mau lasers semiconductor feedback optical kūloko.Ma muli o ka pitch grating liʻiliʻi a me ka koho lōʻihi hawewe maikaʻi, ua maʻalahi ke hoʻokō paʻa i ka puka laina laina haiki paʻa.ʻO ka ʻokoʻa nui ma waena o nā hale ʻelua ʻo ke kūlana o ka grating: ʻo ka DFB structure ka mea maʻamau e puʻunaue i ke ʻano manawa o ka Bragg grating ma loko o ka resonator, a ʻo ka resonator o ka DBR ka mea maʻamau i hoʻokumu ʻia i ka ʻōnaehana hoʻohālikelike a me ka ʻāpana waiwai i hoʻohui ʻia i loko. ka ili hope.Eia kekahi, hoʻohana nā lasers DFB i nā gratings i hoʻopili ʻia me ka hoʻohālikelike haʻahaʻa refractive haʻahaʻa a me ka noʻonoʻo haʻahaʻa.Hoʻohana nā lasers DBR i nā gratings ili me ka ʻokoʻa kuhikuhi refractive kiʻekiʻe a me ka noʻonoʻo kiʻekiʻe.Loaʻa i nā hale ʻelua kahi ākea kikoʻī manuahi a hiki ke hana i ka lōʻihi hawewe me ka ʻole o ka lele ʻana i ke ʻano o nā nanometer, kahi i ʻoi aku ka laulā o ka laser DBR ma mua o kaDFB laser.Eia kekahi, ʻo ka ʻenehana manaʻo hoʻopuka o waho o waho, e hoʻohana ana i nā mea optical o waho e pane i ke kukui puka o ka chip laser semiconductor a koho i ke alapine, hiki ke hoʻomaopopo i ka hana linewidth haiki o ka laser semiconductor.

(2) Nā laser fiber

Loaʻa i nā laser fiber ke kiʻekiʻe o ka hoʻololi ʻana i ka pauma, ka maikaʻi o ka beam maikaʻi a me ka maikaʻi hoʻohui kiʻekiʻe, ʻo ia nā kumuhana noiʻi wela ma ke kahua laser.I ka pōʻaiapili o ka makahiki ʻike, ʻike maikaʻi nā laser fiber me nā ʻōnaehana kamaʻilio fiber optical o kēia manawa i ka mākeke.ʻO ka laser fiber single-frequency me nā pono o ka laulā laina haʻahaʻa, haʻahaʻa haʻahaʻa a me ka coherence maikaʻi i lilo i hoʻokahi o nā kuhikuhi koʻikoʻi o kona hoʻomohala ʻana.

ʻO ka hana mode longitudinal hoʻokahi ke kumu o ka laser fiber no ka hoʻokō ʻana i ka laina ākea ākea, e like me ke ʻano o ka resonator o ka laser fiber frequency hoʻokahi hiki ke hoʻokaʻawale ʻia i ke ʻano DFB, ʻano DBR a me ke ʻano apo.I waena o lākou, ʻo ka loina hana o DFB a me DBR hoʻokahi-frequency fiber lasers e like me ka DFB a me DBR semiconductor lasers.

E like me ka mea i hōʻike ʻia ma ke Kiʻi 1, ʻo ka DFB fiber laser e kākau i ka puʻupuʻu Bragg i hoʻohele ʻia i loko o ka fiber.Ma muli o ka hopena o ka nalu hana o ka oscillator e ka manawa fiber, hiki ke koho ʻia ke ʻano longitudinal ma o ka hāʻawi ʻana i nā manaʻo o ka grating.Hoʻokumu pinepine ʻia ka laser resonator o ka laser DBR e kahi pālua o ka fiber Bragg gratings, a ʻo ke ʻano longitudinal hoʻokahi i koho nui ʻia e ka ʻāpana liʻiliʻi a me ka haʻahaʻa reflectivity fiber Bragg gratings.Eia nō naʻe, ma muli o kona resonator lōʻihi, ʻano paʻakikī a me ka ʻole o ka hana hoʻokae alapine kūpono, ʻo ke apo i hoʻohālikelike ʻia i ke ʻano hopping, a paʻakikī ke hana paʻa i ke ʻano longitudinal mau no ka manawa lōʻihi.

Kiʻi 1, ʻElua hale laina maʻamau o ka alapine hoʻokahinā laser fiber