We present experimental results of enhanced second- and third-harmonic generation efficiency from Fresnel-lensing effects. We obtained enhancement by a factor of 6 in the third-harmonic yield by simply limiting the laser beam with an iris. Higher enhancement factors (up to 16) were obtained with a Fresnel zone plate. The experimental findings are in good agreement with the results of a simple theoretical analysis.
© 2006 Optical Society of America
Original Manuscript: December 16, 2005
Revised Manuscript: January 27, 2006
Manuscript Accepted: January 31, 2006
Stefano Cavalieri, Lorenzo Fini, Emiliano Sali, and Roberto Buffa, "Enhancement of harmonic generation by Fresnel-lensing effects," Opt. Lett. 31, 1298-1300 (2006)