Wavelength-dependent nonlinear wavefront shaping in 3D nonlinear photonic crystal

【摘要】 A 3D nonlinear photonic crystal containing four parallel segments of periodicχ^（2）grating structure is fabricated employing the femtosecond laser poling of ferroelectric Ca_0.28Ba_0.72Nb₂O₆crystal.The second harmonic generation from this foursegment structure is studied with a fundamental Gaussian wave.By tuning the wavelength of the fundamental wave,the second harmonic varies from the Laguerre–Gaussian beam （topological charge l_c=1） to the higher-order Hermite–Gaussian beam and Laguerre–Gaussian again （l_c=-1）.This effect is caused by the wavelength-dependent phase delays introduced by the four-grating structure.Our study contributes to a deeper understanding of nonlinear wave interactions in3D nonlinear photonic crystals.It also offers new possibilities for special beam generation at new frequencies and their control.更多还原

【Abstract】 A 3D nonlinear photonic crystal containing four parallel segments of periodicχ^（2）grating structure is fabricated employing the femtosecond laser poling of ferroelectric Ca_0.28Ba_0.72Nb₂O₆crystal.The second harmonic generation from this foursegment structure is studied with a fundamental Gaussian wave.By tuning the wavelength of the fundamental wave,the second harmonic varies from the Laguerre–Gaussian beam （topological charge l_c=1） to the higher-order Hermite–Gaussian beam and Laguerre–Gaussian again （l_c=-1）.This effect is caused by the wavelength-dependent phase delays introduced by the four-grating structure.Our study contributes to a deeper understanding of nonlinear wave interactions in3D nonlinear photonic crystals.It also offers new possibilities for special beam generation at new frequencies and their control.更多还原