Sum-frequency nonlinear Cherenkov radiation generated on the boundary of bulk medium crystal

Abstract

We demonstrated experimentally a method to generate the sum-frequency Nonlinear Cherenkov radiation (NCR) on the boundary of bulk medium by using two synchronized laser beam with wavelength of 1300 nm and 800 nm. It is also an evidence that the polarization wave is always confined to the boundary. Critical conditions of surface sum-frequency NCR under normal and anomalous dispersion condition is discussed.

Third-order nonlinear phenomenon generated on the inner surface of bulk lithium niobate crystals with magnesium doping

“…Spots 4 and 5 are symmetrical with points 1 and 2 about point 0, respectively. The specific phase-matching mechanisms about spots 0, 1, and 3 are explained in our previous article on interface second harmonic phenomenon [11,12] . Our present research focuses on the generation mechanism of the yellow spot marked 2 in Fig.…”

“…Due to the perfectly phase-matching mechanism, the conversion efficiency of the second harmonic generated on the inner surface of the crystal is relatively high [10][11][12] . The efficiency of nonlinear Cherenkov doubling frequency and sum frequency conversion generated on the crystal surface have also been enhanced [11][12][13][14][15][16][17][18][19][20][21] . Although second-order nonlinear processes on surfaces and interfaces have been extensively studied, thirdorder nonlinear processes are rarely studied.…”

Cherenkov second harmonic generation of femtosecond laser pulses in a homogeneous nonlinear crystal

“…In this case, along with non-phase-matched SHG in the direction of propagation of the fundamental radiation, one can expect the emission of Vavilov-Cherenkov radiation at the SH frequency in the direction determined by the ratio of the phase velocities of the interacting waves (υ 2 /υ 1 ), as schematically shown in figure 1. Note that in the literature, the process under consideration is most often called nonlinear Cherenkov generation of the SH [1][2][3]6], or CND in the case of media with spatial modulation of nonlinear susceptibility χ (2) [9,10,[19][20][21][22].…”

“…According to [17], nonlinear Cherenkov radiation generated unintentionally in many media can be considered as additional nonlinear losses. Nonlinear Cherenkov radiation is observed not only in bulk media, but also in planar waveguides [6,18], on single domain walls [19,20], at the boundary of a nonlinear dielectric [21], and in one-dimensional (1D) [9,10,22], two-dimensional (2D) [23][24][25] and three-dimensional (3D) [26,27] nonlinear photonic crystals (NPCs). In NPCs, a significant increase in the efficiency of nonlinear optical conversion can be achieved.…”

Sequential Three-Dimensional Nonlinear Photonic Structures for Efficient and Switchable Nonlinear Beam Shaping

“…Nonlinear photonic crystals − and nonlinear metasurfaces − have been demonstrated to be important toolkits for nonlinear beam shaping. These nonlinear structures are constructed by artificially engineering the spatial distribution of nonlinear coefficients, which provides regular or irregular multiple reciprocal vectors to shape nonlinear waves in the far field through quasi-phase matching (QPM), , nonlinear Raman–Nath diffraction, nonlinear Cerenkov radiation, nonlinear Bragg refraction, and so on. In particular, the QPM scheme largely increased the nonlinear conversion efficiency for shaping nonlinear quantum sources .…”