Hoʻolālā ala optical o ka laser mode-locked 66-femtosecond

Hoʻolālā ala optical o ka 66-femtosecondlaser laka ʻano
ʻO kēia laser mode-locked 66-femtosecond he lua linear all-polarization-maintaining ytterbium-doped fiber laser me kahi mea hoʻololi pae non-reciprocal. Hoʻokō ia i ka 147 MHz fundamental frequency mode-locking. Ma ka hoʻoponopono ʻana i ka mamao ma waena o nā gratings, loaʻa kahi laulā spectral o 39.8 nm a me ka laulā pulse o 66 fs ma hope o ka compression waho. Ma ka mana pump kiʻekiʻe, hoʻokō ʻia ka lua-kauoha a me ke kolu-kauoha harmonic mode-locking me nā alapine hana hou o 294.1 MHz a me 442.3 MHz.

Ka wehewehe ʻana o ke ala ʻōniʻoniʻo:
ʻO ka resonator nā ʻāpana optical spatial ma nā ʻaoʻao ʻelua a me ka ʻāpana fiber mālama polarization ma waena. ʻO ka ʻāpana spatial hema e komo pū ana me kahi aniani hoʻākāka piha (M1), kahi papa nalu λ/8 (EWP), a me kahi Faraday rotator (FR). Hiki ke hoʻohana ʻia ka hui pū ʻana o EWP a me FR ma ke ʻano he mea hoʻololi pae non-reciprocal, e hāʻawi ana i ka non-reciprocal phase bias, a laila e hoʻonui ai i ka hiki ke hoʻomaka ponoʻī. ʻO ka ʻāpana fiber he mea hoʻohui i ka wavelength division multiplexing - collimator (WDM-Collimator), 62 cm ytterbium-doped polarization-maintaining fiber (Yb401-PM, CORACTIVE), a me kahi optical fiber collimator (Col). Hoʻopuka ʻia ka fiber loaʻa e kahi diode laser 976 nm hoʻokahi-ʻano (LD) me ka mana pamu kiʻekiʻe loa o 1.4 W. ʻO ka ʻāpana spatial ʻākau he pā hapalua nalu (HWP), kahi polarization beam splitter (PBS), kahi hui grating (LightSmyth T-1000-1040-3212-94), a me kahi aniani noʻonoʻo holoʻokoʻa (M2). ʻO ka hui grating hoʻoili me ka nui o ka laina o 1000 laina/mm e hāʻawi i ka uku hoʻopuehu intra-cavity. Hiki ke hoʻoponopono ʻia ka mamao ma waena o nā gratings ʻelua e kahi kahua. ʻO ka lōʻihi o ka hakahaka manuahi mai ka collimator a i nā aniani noʻonoʻo ʻelua ma nā ʻaoʻao ʻelua he 5.5 cm a me 6.5 cm. ʻO kalaserhoʻopuka i nā pulse ma ke ʻano polarized linearly mai ka PBS.
Kumu hana:
Hoʻomaka ka pulse maʻamau mua i hoʻouna ʻia ma o ka loop intracavity mai PBS a hoʻouna ʻia i M1. I ka wā mua, e hoʻokaʻawale ka HWP i ka pulse i ʻelua mau ʻāpana orthogonal, a laila e komo i ka fiber optical mālama polarization a hoʻolaha ma nā axes wikiwiki a lohi. Hoʻoholo ʻia ka lakio ikaika o nā pulse ma nā axes orthogonal ʻelua e ke kihi rotation (θh) o ka HWP. I ka wā o ka hoʻolaha ʻana i loko o ka fiber optical, ma muli o nā hopena nonlinear, ʻo ka ikaika asymmetric o nā pulse polarized orthogonal e hoʻoulu ai i nā neʻe pae nonlinear e pili ana i ka ikaika. ʻO ke aniani hope M1 e hiki ai i nā pulse orthogonal ke hele ma waena o ka mea hoʻololi pae ʻelua a hoʻi i ka fiber optical mālama polarization. Loaʻa i nā pulse orthogonal kahi neʻe pae non-reciprocal π/2 a hoʻololi i ka axis optical hoʻolaha. ʻO ka mismatch velocity hui ma waena o nā pulse polarized orthogonal e alakaʻi i ka uku o ka hopena deviation. ʻO ka hope, hōʻiliʻili ka pulse i nā neʻe pae nonlinear like ʻole a loaʻa i ka hoʻopilikia ma PBS. Ma ke ʻano he polarizer, ʻae ʻo PBS i nā pulse kūlana polarization kūpono e hele ma waena, ʻoiai ke koena e hōʻike ʻia ana mai loko mai o ka lua. Hoʻokani kēia kaʻina hana i ke kuleana o kahi mea hoʻomoʻa saturable artificial i loko o kēia lua linearlaser ʻōpae. Ke hoʻemi hou ʻia ka mamao o ka hui grating i 3.2 mm, lilo ka ʻaoʻao hema o ka spectrum i ʻoi aku ka piʻi. I kēia manawa, maikaʻi ka hoʻolaha ʻupena lua, a loaʻa ka ikehu pulse hoʻokahi kiʻekiʻe loa o 3.57 nJ. ʻO ke kaha pilina ponoʻī pulse i loaʻa ma o ka hoʻopili waho o ka pulse me ka laulā spectral 39.8 nm ākea loa i hoʻopili ʻia e kahi hana Gaussian, ʻo ia hoʻi he 66 fs.