We study theoretically the Čerenkov-type second-harmonic generation by a Gaussian beam in quadratic nonlinear
media with periodically reverted ferroelectric domains. In particular, we consider the role of fundamental beam
width on the harmonic emission process. We show that varying the beam width of the fundamental wave not only
affects the strength of the emitted Čerenkov harmonic signal but also changes the sensitivity of the emission
process to wavelength tuning.
Sheng, Y. [et al.]. Theoretical study of Cerenkov-type second-harmonic generation in periodically poled ferroelectric crystals. "Journal of the Optical Society of America B. Optical physics", Març 2012, vol. 29, núm. 3, p. 312-318.