Ngā tikanga whakarea whatu me tā rātou hononga mō te maramara-i-runga: he arotake

Ngā tikanga whakarea whatu me tā rātou hononga mō te maramara-i-runga me tewhakawhitiwhiti muka whatu: he arotake

He kaupapa rangahau nui ngā tikanga whakarea whatu, ā, kei te whakahaerehia e ngā tohunga o te ao katoa he rangahau hōhonu i tēnei mara. I roto i ngā tau, he maha ngā hangarau whakarea whatu pērā i te whakarea wehewehe roangaru (WDM), te whakarea wehewehe aratau (MDM), te whakarea wehewehe ātea (SDM), te whakarea polarization (PDM) me te whakarea nekehanga koki ā-orbital (OAMM). Mā te hangarau whakarea wehewehe roangaru (WDM) ka taea te tuku i ngā tohu whatu e rua, neke atu rānei, o ngā roangaru rerekē i te wā kotahi mā te muka kotahi, me te whakamahi katoa i ngā āhuatanga ngaronga iti o te muka i roto i te whānuitanga roangaru nui. I tuatahitia te ariā e Delange i te tau 1970, ā, tae noa ki te tau 1977 ka tīmata te rangahau taketake o te hangarau WDM, e arotahi ana ki te tono o ngā whatunga whakawhitiwhiti kōrero. Mai i taua wā, me te whanaketanga tonu omuka whatu, pūtake mārama, pūoko whakaahuame ētahi atu mara, kua tere ake hoki te tūhuratanga a te tangata i te hangarau WDM. Ko te painga o te whakarea pōraritanga (PDM) ko te nui o te tuku tohu ka taea te whakanui ake, nā te mea ka taea te tohatoha i ngā tohu motuhake e rua i te tūranga pōraritanga orthogonal o te hihi mārama kotahi, ā, ka wehea ngā hongere pōraritanga e rua, ka tautuhia motuhaketia i te pito whiwhi.

I te mea kei te piki haere tonu te hiahia mō ngā tere raraunga teitei ake, kua tino rangahauhia te taumata whakamutunga o te herekore o te whakarea, arā, te wāhi, i roto i te tekau tau kua hipa. I roto i ēnei, ko te whakarea wehewehe aratau (MDM) te nuinga o te wā ka whakaputaina e ngā tuku N, e whakatinanahia ana e te whakarea aratau wāhi. Hei whakamutunga, ka tukuna te tohu e tautokona ana e te aratau wāhi ki te muka aratau-iti. I te wā o te horapa tohu, ka whakaarohia ngā aratau katoa i runga i te roangaru kotahi hei waeine o te hongere nui o te whakarea Wehenga Wāhi (SDM), arā, ka whakanuia, ka whakaitihia, ka tāpirihia i te wā kotahi, me te kore e taea te whakatutuki i te tukatuka aratau motuhake. I roto i te MDM, ka tohaina ngā āhua wāhi rerekē (arā, ngā āhua rerekē) o te tauira ki ngā hongere rerekē. Hei tauira, ka tukuna he hongere ki runga i te hihi laser he rite te āhua ki te tapatoru, te tapawhā, te porowhita rānei. He uaua ake ngā āhua e whakamahia ana e te MDM i roto i ngā tono o te ao tūturu, ā, he āhuatanga pāngarau me te tinana ahurei. Koinei pea te hangarau tino angitu i roto i te tuku raraunga muka whatu mai i te tekau tau 1980. Ka whakaratohia e te hangarau MDM he rautaki hou hei whakatinana i ngā hongere maha atu me te whakanui ake i te kaha hononga ma te whakamahi i te kaikawe roangaru kotahi. Ko te nekehanga koki porowhita (OAM) he āhuatanga ā-tinana o ngā ngaru hikohiko e whakatauhia ana te ara horapa e te taha o te ngaru porowhita. Nā te mea ka taea te whakamahi i tēnei āhuatanga hei whakatū i ngā hongere motuhake maha, ka taea e te whakarea nekehanga koki porowhita ahokore (OAMM) te whakanui ake i te tere tuku i roto i ngā tuku teitei-ki-ira (pēnei i te whakahokinga ahokore, te whakamua rānei).