Encoding of holographic grating and periodic nano-structure by femtosecond laser pulse
Encoding of holographic grating and periodic nano-structure by femtosecond laser pulse
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DOI：
10.1016/s0169-4332(02)00446-4
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发表时间：
2002-09
影响因子：
6.7
通讯作者：
M. Hirano;K. Kawamura;H. Hosono
中科院分区：
文献类型：
--
作者：
M. Hirano;K. Kawamura;H. Hosono
充分利用飞秒脉冲的超短时域和良好的相干性等特性，我们成功地在陶瓷、半导体、金属和塑料等多种材料表面或表面下编码出了微光栅和多维周期性纳米结构。在编码装置中，锁模钛宝石激光器输出的再生放大脉冲被分成两束，然后在材料的顶面或内部重叠，得到一个直径为50μm的光斑。两光束的光路应在± 30μm范围内精确调节，以产生干涉。利用空气中的三次谐波产生（THG），使调整不受碰撞角度的限制成为可能。以激光烧蚀产生的表面浮雕型光栅、石英玻璃结构变化引起的折射率型光栅、金刚石中的嵌入式光栅、铌酸锂波导中的光耦合和光去耦光栅以及石英玻璃中的二维纳米结构为例进行了演示。我们希望本技术开辟了一个前沿的衍射光学与周期性纳米结构的形成适用于新兴的设备，如平面波导，量子点和光子晶体。
By fully utilizing distinct features of femtosecond (FS) pulses such as ultra-short time domain and good coherence, we have successfully encoded micro-gratings and multi-dimensional periodic nano-structures either on or beneath surfaces of versatile materials including dielectrics, semiconductors, metals and plastics. In the setup for the encoding, a regenerative amplified pulse from a mode locked Ti:sapphire laser was split into two beams, then overlapped on the top surface or in the interior of the materials to give a ∼50μm spot. The optical paths of the two beams should be adjusted precisely within ∼30μm to induce the interference. Use of the third harmonic generation (THG) from air made the adjustment possible not restricted from colliding angles. Surface relief type gratings due to laser ablation and refractive index type gratings resulted from structural changes in silica glasses, embedded gratings in diamond, gratings capable of light coupling and decoupling to a LiNbO3wave guide, and two-dimensional nano-structures in silica glass are demonstrated as examples. We expect the present technique to open up a frontier of diffractive optics with the formation of periodic nano-structures applicable to emerging devices such as planar wave guides, quantum dots and photonic crystals.