▁fish ing ▁net . ▁ ▁In ▁the ▁experiment , ▁when ▁the ▁met as creen ▁was ▁hit ▁by ▁ 3 . 6   G Hz ▁mic row aves , ▁it ▁re - rad i ated ▁mic row aves ▁of ▁the ▁same ▁frequency ▁that ▁were ▁out ▁of ▁phase , ▁thus ▁can cell ing ▁out ▁ref lections ▁from ▁the ▁object ▁being ▁hidden . ▁ ▁The ▁device ▁only ▁cancel led ▁out ▁the ▁scatter ing ▁of ▁mic row aves ▁in ▁the ▁first ▁order . ▁The ▁same ▁research ers ▁published ▁a ▁paper ▁on ▁" pl as mon ic ▁clo aking " ▁the ▁previous ▁year . ▁ ▁How ell / Cho i ▁clo aking ▁device ▁ ▁University ▁of ▁Ro chester ▁physics ▁professor ▁John ▁How ell ▁and ▁gradu ate ▁student ▁Joseph ▁Ch oi ▁have ▁announced ▁a ▁scal able ▁clo aking ▁device ▁which ▁uses ▁common ▁optical ▁l enses ▁to ▁achieve ▁visible ▁light ▁clo aking ▁on ▁the ▁macro scop ic ▁scale , ▁known ▁as ▁the ▁" R och ester ▁Clo ak ". ▁The ▁device ▁consists ▁of ▁a ▁series ▁of ▁four ▁l enses ▁which ▁direct ▁light ▁ray s ▁around ▁objects ▁which ▁would ▁otherwise ▁occ l ude ▁the ▁optical ▁path way . ▁ ▁Clo aking ▁in ▁mechan ics ▁The ▁concepts ▁of ▁clo aking ▁are ▁not ▁limited ▁to ▁opt ics ▁but ▁can ▁also ▁be ▁transferred ▁to ▁other ▁fields ▁of ▁physics . ▁For ▁example , ▁it ▁was ▁possible ▁to ▁clo ak ▁ac oust ics ▁for ▁certain ▁frequencies ▁as ▁well ▁as ▁touch ing ▁in ▁mechan ics . ▁This ▁rend ers ▁an ▁object ▁" in visible " ▁to ▁sound