2D wave-front shaping in optical superlattices using nonlinear volume holography

Abstract

Nonlinear volume holography is employed to realize arbitrary wave-front shaping during nonlinear processes with properly designed 2D optical superlattices. The concept of a nonlinear polarization wave in nonlinear volume holography is investigated. The holographic imaging of irregular patterns was performed using 2D LiTaO₃ crystals with fundamental wave propagating along the spontaneous polarization direction, and the results agree well with the theoretical predictions. This Letter not only extends the application area of optical superlattices, but also offers an efficient method for wave-front shaping technology.

Dynamic computer-generated nonlinear-optical holograms

“…In recent years, shaping a generated wave front of a light wave via nonlinear processes has attracted more and more interest, with a variety of methods having been proposed. One of the methods was to design the spatial structure of nonlinear photonic crystals (NPCs) to shape the phase of the generated second-harmonic (SH) beam [15][16][17][18][19][20][21][22][23][24][25][26][27]. The holography concept has also been introduced to the nonlinear field by shaping the nonlinear light wave in one-dimensional (1D) or 2D manners [16][17][18].…”

“…The holography concept has also been introduced to the nonlinear field by shaping the nonlinear light wave in one-dimensional (1D) or 2D manners [16][17][18]. In addition, nonlinear volume holography has also been proposed and realized in recent years [19,20]. Another method to shape the nonlinear light wave was assisted by a functional facet [28].…”

“…Limited by the domain inversion technique [34], only 1D SH beam shaping can be realized [15,19,21,26] using quasiphase matching schemes. The method to realize 2D SH shaping proposed by Shapira and co-workers is that of the fundamental Gaussian beam propagating along the z axis of NPCs [16][17][18]20]. However, the quite low conversion efficiency is caused by the phase mismatch.…”

“…However, the quite low conversion efficiency is caused by the phase mismatch. Our method not only allows for shaping the amplitude and phase of the SH at the same time in 2D cases, but also possesses a higher conversion efficiency than the methods in [16][17][18]20] as the FW can be propagating along any direction of the nonlinear crystal (in this paper, the FW propagates along the BPM direction). However, it should be mentioned that, for the purpose of keeping the nondiffraction assumption valid, long transverse modulated periods of the FW and the sufficient short interaction length need to be satisfied at the same time.…”

“…Generated SH beams in experiment corresponding to (a) LG 10 , (b) LG20 , and (c) LG11 and cross section of the simulated (solid red curve) and measured (dashed blue curve) intensities corresponding to (d) LG 10 , (e) LG20 , and (f) LG11 .…”