Lensing by gravitational waves in scalar-tensor gravity: Einstein frame   analysis
  The amplification of a light beam due to intervening gravitational waves is studied. The previous Jordan frame result according to which the amplification is many orders of magnitude larger in scalar-tensor gravity than in general relativity does not hold in the Einstein conformal frame. Lensing by gravitational waves is discussed in relation to the ongoing and proposed VLBI observations aimed at detecting the scintillation effect. 
Valerio Faraoni and Edgard Gunzig