Surface radiation from non-linear optical polarisation

Single Domain Wall Effect on Parametric Processes via Cherenkov-Type Phase Matching

“…When the phase velocity of the fundamental beam v in the waveguide is larger than the phase velocity of second harmonic (SH) v in the substrate, the harmonic radiation emits into the substrate at Cherenkov angle. [2][3][4] We can see that the pattern of CSHG is determined by the geometry of the stimulated nonlinear polarization material. In our experiment of CSHG at domain wall, the well-collimated CSH indicates only the planar domain wall to be the only stimulated nonlinear polarization material, the typical width of which is believed to be less than 100 nm in ferroelectrics.…”

“…It can be seen that CR occurs only when v > v . A similar phenomenon called Cherenkov second harmonic generation (CSHG) is observed in nonlinear optics processes, [2][3][4] when the phase velocity of nonlinear polarization propagates faster than the phase velocity of free light of second harmonics in medium. While these two processes are similar, CSHG has unique features.…”

Nonlinear Diffraction from a Virtual Beam

“…The strong external ring in Fig. 1(b) is due to the Č erenkov SH radiation [11,12,14]. This conical SH wave has a cone angle defined solely by the longitudinal phase-matching condition, k 2 cos ¼ 2k 1 .…”

Nonlinear Cherenkov radiation at the interface of two different nonlinear media

“…Nonlinear Cherenkov radiation (NCR) [1], an extension of the Cherenkov radiation well known in particle physics to nonlinear optics, has attracted considerable interest in recent years. In NCR, when the phase velocity of the fundamental wave (FW) exceeds that of the second harmonic (SH) wave, the SH radiates at an angle θ = arccos(ν 2 /ν 1 ), where ν 1 and ν 2 denote the phase velocities of the FW and SH, respectively.…”