▁of ▁the ▁absolute ▁values ▁of ▁the ▁two ▁components ▁of ▁Jones ▁vectors ▁is ▁proportional ▁to ▁the ▁intensity ▁of ▁light . ▁ ▁It ▁is ▁common ▁to ▁normal ize ▁it ▁to ▁ 1 ▁at ▁the ▁starting ▁point ▁of ▁calculation ▁for ▁simpl ification . ▁ ▁It ▁is ▁also ▁common ▁to ▁const rain ▁the ▁first ▁component ▁of ▁the ▁Jones ▁vectors ▁to ▁be ▁a ▁real ▁number . ▁This ▁disc ards ▁the ▁overall ▁phase ▁information ▁that ▁would ▁be ▁needed ▁for ▁calculation ▁of ▁inter ference ▁with ▁other ▁be ams . ▁ ▁Note ▁that ▁all ▁Jones ▁vectors ▁and ▁matrices ▁in ▁this ▁article ▁employ ▁the ▁convention ▁that ▁the ▁phase ▁of ▁the ▁light ▁wave ▁is ▁given ▁by ▁, ▁a ▁convention ▁used ▁by ▁He cht . ▁ ▁Under ▁this ▁convention , ▁increase ▁in ▁ ▁( or ▁) ▁indicates ▁ret ard ation ▁( delay ) ▁in ▁phase , ▁while ▁decrease ▁indicates ▁advance ▁in ▁phase . ▁ ▁For ▁example , ▁a ▁Jones ▁vectors ▁component ▁of ▁ ▁() ▁indicates ▁ret ard ation ▁by ▁ ▁( or ▁ 9 0 ▁degree ) ▁compared ▁to ▁ 1 ▁( ). ▁ ▁Circ ular ▁polar isation ▁described ▁under ▁Jones ' ▁convention ▁is ▁called ▁: ▁" From ▁the ▁point ▁of ▁view ▁of ▁the ▁receiver ". ▁Col lett ▁uses ▁the ▁opposite ▁definition ▁for ▁the ▁phase ▁( ). ▁Circ ular ▁polar isation ▁described ▁under ▁Col lett ' s ▁convention ▁is ▁called ▁: ▁" From ▁the ▁point ▁of ▁view ▁of ▁the ▁source ". ▁ ▁The ▁reader ▁should ▁be ▁w ary ▁of ▁the ▁choice ▁of ▁convention ▁when ▁consult ing ▁references ▁on ▁the ▁Jones ▁calculus . ▁ ▁The