m inton ▁players ▁at ▁the ▁ 2 0 1 8 ▁Asian ▁Games ▁Category : As ian ▁Games ▁compet itors ▁for ▁South ▁Korea ▁Category : Univers ia de ▁gold ▁medal ists ▁for ▁South ▁Korea ▁Category : Univers ia de ▁bronze ▁medal ists ▁for ▁South ▁Korea ▁Category : Univers ia de ▁medal ists ▁in ▁bad m inton <0x0A> </s> ▁A ▁spatial ▁filter ▁is ▁an ▁optical ▁device ▁which ▁uses ▁the ▁principles ▁of ▁Fourier ▁opt ics ▁to ▁alter ▁the ▁structure ▁of ▁a ▁beam ▁of ▁light ▁or ▁other ▁elect romagnet ic ▁radiation , ▁typically ▁coh er ent ▁las er ▁light . ▁Sp atial ▁filtering ▁is ▁commonly ▁used ▁to ▁" clean ▁up " ▁the ▁output ▁of ▁las ers , ▁removing ▁aber r ations ▁in ▁the ▁beam ▁due ▁to ▁imper fect , ▁dirty , ▁or ▁dam aged ▁opt ics , ▁or ▁due ▁to ▁variations ▁in ▁the ▁las er ▁gain ▁medium ▁itself . ▁This ▁filtering ▁can ▁be ▁applied ▁to ▁transmit ▁a ▁pure ▁trans verse ▁mode ▁from ▁a ▁mult im ode ▁las er ▁while ▁blocking ▁other ▁modes ▁em itted ▁from ▁the ▁optical ▁reson ator . ▁The ▁term ▁" filter ing " ▁indicates ▁that ▁the ▁des irable ▁struct ural ▁features ▁of ▁the ▁original ▁source ▁pass ▁through ▁the ▁filter , ▁while ▁the ▁und es irable ▁features ▁are ▁blocked . ▁Appar atus ▁which ▁follows ▁the ▁filter ▁effectively ▁sees ▁a ▁higher - quality ▁but ▁lower - power ed ▁image ▁of ▁the ▁source , ▁instead ▁of ▁the ▁actual ▁source ▁directly . ▁An ▁example ▁of ▁the ▁use ▁of ▁spatial ▁filter ▁can ▁be ▁seen ▁in ▁advanced ▁setup ▁of ▁micro