Are there anythings which can generate stonger surface SHG ?

From: hh (bighuiw_at_sohu.com)
Date: 09/29/04 

Date: 29 Sep 2004 11:17:59 -0700

We are searching something which have higher coversion efficiency of
SHG. We do not want to use crystal. Now we are using GaAs wafer as SHG
mirror. I did find the number of coversion efficiency. Pls tell me if
you know. Is there something else, which we can order , with stronger
surface SHG than GaAs?

Thanks

HH