Isantya apho umphambili wenqwelomoya ye-monochromatic usasazeke kwicala eliqhelekileyo libizwa ngokuba sisantya sesigaba samaza. Isantya esihamba ngaso amandla amaza okukhanya kuthiwa yi-ray velocity. Icala ohamba kulo ukukhanya njengoko kubonwa liliso lomntu licala ekuhamba kulo ukukhanya.

Kwikristale enye engeyiyo eyemagnetic, isantya sesigaba sokukhanya okucwangcisiweyo kwamaza sijonge kwicala lokufuduswa kombane. D kunye nokuqina kwemagnethi H, ngelixa indlela yokusasazwa kwamandla amaza okukhanya i-perpendicular to H kunye nokuqina kwebala lombane E. I-dielectric constant ye-anisotropic optical media yi-second-order tensor.D kwaye E ngokuqhelekileyo azihambelani, ngoko isalathiso sesantya sesigaba v kunye nesantya somgca v_r azihambelani ngokubanzi. I-Angle ifakiwe α phakathi kwabo kuthiwa yi-discrete ai-ngle, engumsebenzi wesalathiso sesantya sesigaba (okanye isantya semitha) kunye nendlela D (okanye E) (njengoko kubonisiwe kulo mfanekiso ungezantsi). Isantya sesigaba kunye nesantya somgca asilingani ngokubanzi, kwaye ubudlelwane phakathi kwabo buv=v_rcosα.

Umlinganiselo wesantya ukukhanya ohamba ngaso kwivacuum (c) kwisantya sesigaba sayo v kwicala elinikiweyo kwi-anisotropic optical medium ibizwa ngokuba sisalathiso se-refractive saloo ndlela. Ngokufanayo, umlinganiselo wec kwisantya semitha kwicala elithile n_r=c/v_r ibizwa ngokuba sisalathiso se-refractive seray ukuya kwelo cala.

WISOPTIC wave-iipleyiti