ʻIkepili o nā lasers pulsed

ʻIkepili onā lasers pulsed

ʻO ke ala pololei loa e hoʻohua ailaserʻO nā pulses ka hoʻohui ʻana i kahi modulator i waho o ka laser hoʻomau. Hiki i kēia ʻano hana ke hana i ka pulse picosecond wikiwiki loa, ʻoiai he maʻalahi, akā ʻaʻole hiki i ka ikehu kukui hoʻonele a me ka mana kiʻekiʻe ke ʻoi aku ma mua o ka mana kukui hoʻomau. No laila, ʻo kahi ala ʻoi aku ka maikaʻi e hana ai i nā pulses laser ʻo ia ke modulate i loko o ka lua laser, e mālama ana i ka ikehu i ka manawa off-time o ke kaʻa pulse a hoʻokuʻu iā ia i ka manawa. ʻO nā ʻano hana maʻamau ʻehā i hoʻohana ʻia e hana i nā pulses ma o ka modulation cavity laser ʻo ia ka hoʻololi loaʻa, Q-switching (loss switching), cavity emptying, a me ke mode-locking.

Hoʻopuka ka hoʻololi loaʻa i nā pulse pōkole ma ka hoʻololi ʻana i ka mana pamu. No ka laʻana, hiki i nā lasers semiconductor gain-switched ke hoʻopuka i nā pulse mai kekahi mau nanoseconds a i hoʻokahi haneli picoseconds ma o ka modulation o kēia manawa. ʻOiai he haʻahaʻa ka ikehu pulse, he maʻalahi loa kēia ʻano hana, e like me ka hāʻawi ʻana i ka alapine hana hou hiki ke hoʻololi ʻia a me ka laulā pulse. I ka makahiki 2018, ua hōʻike nā mea noiʻi ma ke Kulanui o Tokyo i kahi laser semiconductor femtosecond gain-switched, e hōʻike ana i kahi holomua i loko o kahi bottleneck loea 40 makahiki.

Hoʻopuka pinepine ʻia nā pulse nanosecond ikaika e nā lasers Q-switched, i hoʻopuka ʻia i kekahi mau huakaʻi puni i loko o ke ana, a aia ka ikehu pulse ma ka pae o kekahi mau millijoules a i kekahi mau joules, ma muli o ka nui o ka ʻōnaehana. Hoʻopuka nui ʻia nā pulse picosecond a me femtosecond me ka ikehu waena (ma lalo o 1 μJ) e nā lasers mode-locked. Aia kekahi a ʻoi aku paha nā pulse ultrashort i loko o ka resonator laser e hoʻomau nei i ka pōʻaiapuni. Hoʻouna kēlā me kēia pulse intracavity i kahi pulse ma o ke aniani hoʻopili hoʻopuka, a ʻo ka refrequency ma waena o 10 MHz a me 100 GHz. Hōʻike ka kiʻi ma lalo nei i kahi dispersion maʻamau piha (ANDi) dissipative soliton femtosecondhāmeʻa laser fiber, ʻo ka hapa nui o ia mea hiki ke kūkulu ʻia me ka hoʻohana ʻana i nā ʻāpana maʻamau o Thorlabs (fiber, lens, mount a me ka papa hoʻoneʻe).

Hiki ke hoʻohana ʻia ke ʻano hana hoʻokahe lua noNā lasers i hoʻololi ʻia me Qe loaʻa nā pulse pōkole a me nā lasers mode-locked e hoʻonui i ka ikehu pulse me ka refrequency haʻahaʻa.

Nā pulse kikowaena manawa a me ke alapine (frequency)
ʻO ke ʻano linear o ka pulse me ka manawa he mea maʻalahi ia a hiki ke hōʻike ʻia e nā hana Gaussian a me sech². ʻO ka manawa pulse (i ʻike ʻia hoʻi ʻo ka laulā pulse) ka mea i hōʻike pinepine ʻia e ka waiwai o ka laulā hapalua kiʻekiʻe (FWHM), ʻo ia hoʻi, ka laulā ma waena o ka mana optical ma ka liʻiliʻi he hapalua o ka mana kiʻekiʻe; Hoʻopuka ka laser Q-switched i nā pulse pōkole nanosecond ma o
Hoʻopuka nā lasers mode-locked i nā pulse ultra-short (USP) ma ke ʻano o nā ʻumi picoseconds a i nā femtoseconds. Hiki i nā mea uila wikiwiki ke ana i nā ʻumi picoseconds, a hiki ke ana ʻia nā pulse pōkole me nā ʻenehana optical wale nō e like me nā autocorrelators, FROG a me SPIDER. ʻOiai ʻaʻole loli iki nā pulse nanosecond a i ʻole nā ​​​​pulse lōʻihi i ko lākou laulā pulse i ko lākou hele ʻana, ʻoiai ma nā mamao lōʻihi, hiki ke hoʻopilikia ʻia nā pulse ultra-short e nā kumu like ʻole:

Hiki i ka hoʻopuehu ke hopena i ka hoʻonui nui ʻana o ka pulse, akā hiki ke hoʻopili hou ʻia me ka hoʻopuehu ʻē aʻe. Hōʻike ka kiʻikuhi ma lalo nei pehea e uku ai ka Thorlabs femtosecond pulse compressor no ka hoʻopuehu microscope.

ʻAʻole pili pololei ka nonlinearity i ka laulā o ka pulse, akā hoʻonui ia i ka bandwidth, e hoʻolilo ana i ka pulse i mea maʻalahi i ka hoʻopuehu ʻana i ka wā o ka hoʻolaha ʻana. Hiki i kēlā me kēia ʻano fiber, me nā mea loaʻa ʻē aʻe me ka bandwidth palena, ke hoʻopilikia i ke ʻano o ka bandwidth a i ʻole ka pulse ultra-short, a ʻo ka emi ʻana o ka bandwidth hiki ke alakaʻi i ka hoʻonui ʻana i ka manawa; Aia kekahi mau hihia kahi e pōkole ai ka laulā o ka pulse o ka pulse chirped ikaika ke lilo ka spectrum i mea narrower.