Subject: Is there simple device producing circular polarized light?

I know when a random polarized light transmits a polarizor and a 1/4 wave 
plate it turns into a circular polarized light!But that is only restrict to 
the monochrome light(light in a sigle wave length),so I ask whether there is a 
simple device to turn common light with a wide range of wave length(e.g. 
sunlight)in to relatively pure circular polarized light!
Thanks!

Re: Is there simple device producing circular polarized light?