Ngokubanzi, ubukhulu bokukhanya kwelaser yiGaussian, kwaye kwinkqubo yokusetyenziswa kwe-laser, inkqubo ye-optical idla ngokusetyenziswa ukuguqula umqadi ngokufanelekileyo.

Ngokwahlukileyo kwithiyori yomgca we-geometric optics, ithiyori yokuguqulwa kwe-optical ye-Gaussian beam ayihambelani, ehambelana ngokusondeleyo neeparitha ze-laser beam ngokwayo kunye nendawo ehambelanayo yenkqubo ye-optical.

Zininzi iiparamitha zokuchaza umqadi we-laser ye-Gaussian, kodwa ubudlelwane phakathi kweradiyasi yendawo kunye nendawo esinqeni yomqadi ihlala isetyenziswa ekusombululeni iingxaki ezisebenzayo. Oko kukuthi, iradius esinqeni somgca wesiganeko (ω₁) kunye nomgama wenkqubo yokuguqulwa kwamehlo (z₁) ziyaziwa, kwaye emva koko iradiyasi yesinqe esiguquliweyo (ω₂), indawo yokuma esinqeni (z₂) kunye neradiyasi yendawo (ω₃) kuyo nayiphi na indawo (z) zifunyenwe. Gxininisa kwi-lens, kwaye ukhethe izikhundla zangaphambili kunye nezinqe zangasemva ze-lens njenge-reference plane 1 kunye ne-reference plane 2 ngokulandelanayo, njengoko kuboniswe kwi-Fig.

                     Umzobo 1 Ukuguqulwa kweGauss nge-lens encinci

Ngokutsho kweparameter q ithiyori yeGaussian beam, i q₁ kwaye q₂ kwezi nqwelo-moya zimbini zingachazwa ngolu hlobo:

Kule fomula ingentla: I f_e1 kwaye f_e2 ngokulandelelanayo iiparamitha ze-confocus phambi nasemva koguqulo lomqadi weGaussian. Emva kokuba umqa weGaussian udlula kwindawo ekhululekile z₁, ilensi ebhityileyo enobude obugxile F kunye nendawo ekhululekile z₂, ngokutsho kwe A B C D Usulelo lwethiyori yematrix, oku kulandelayo kunokufumaneka:

Okwangoku, q₁ kwaye q₂ ukwanelisa olu budlelwane bulandelayo:

Ngokudibanisa ezi fomyula zingasentla kunye nokwenza iindawo zokwenyani kunye nezo zicingelwayo kuzo zombini iziphelo zeequation zilingane ngokulandelelana, sinokufumana:

I-Equations (4) - (6) lubudlelwane benguqu phakathi kwesinqe esinqeni kunye nobukhulu bebala le-Gaussian beam emva kokudlula kwi-lens encinci.