Hirose Kazuyoshi, Takiguchi Yu, Sugiyama Takahiro, Nomoto Yoshiro, Uenoyama Soh, Kurosaka Yoshitaka
Opt Express. 2018 Nov 12;26(23):29854-29866. doi: 10.1364/OE.26.029854.
Static arbitrary two-dimensional beam patterns have been demonstrated using on-chip size "integrable spatial-phase-modulating surface-emitting lasers," which use the band edge mode of a two-dimensional photonic crystal as an in-plane resonator, while the spatial phase of the lightwaves of the band edge mode are simultaneously modulated in a holographic manner by a local positional shift of holes from their lattice points. Meanwhile, the beam patterns include a spot beam in the surface-normal direction (0th-order beam), which corresponds to components of vertical diffraction of the band edge modes without spatial phase modulation. A promising method, used to remove the 0th-order beam, uses a structure that prohibits the vertical diffraction of band edge modes. For this purpose, we set the period of the virtual photonic crystal structure from the conventional Γ band edge to the Μ band edge, where vertical diffraction is prohibited. Moreover, the additional spatial phase modulation that cancels the in-plane component of the wavevectors of the lightwaves of the band edge modes at the Μ band edge are also imposed to output the beam patterns vertically. As a result, we successfully demonstrated two-dimensional beam patterns without a spot beam in the surface-normal direction.
利用片上尺寸的“可集成空间相位调制表面发射激光器”已展示出静态任意二维光束图案，该激光器将二维光子晶体的带边模式用作面内谐振器，同时通过空穴相对于其晶格点的局部位置偏移以全息方式同时调制带边模式光波的空间相位。同时，光束图案包括沿表面法线方向的点光束（零阶光束），它对应于无空间相位调制的带边模式的垂直衍射分量。一种用于去除零阶光束的有前景的方法是使用一种禁止带边模式垂直衍射的结构。为此，我们将虚拟光子晶体结构的周期从传统的Γ带边设置到Μ带边，在Μ带边垂直衍射被禁止。此外，还施加额外的空间相位调制以抵消Μ带边处带边模式光波波矢的面内分量，从而垂直输出光束图案。结果，我们成功展示了在表面法线方向上没有点光束的二维光束图案。
