Nanostructure of Technology for Making Photonic Crystals

光学微腔器件（例如垂直腔面发射激光器（VCSEL）[1]）过去的快速出现可以在很大程度上归因于在半导体晶体生长期间可获得的层厚度控制的高精度。 高反射率反射镜可以以亚纳米精度生长，以在垂直维度上限定高=Q腔。 最近，通过制造二维和三维周期性结构来微制造高反射率镜也成为可能。 这些周期性的“光子晶体”可以被设计为打开频带，在该频带内，电磁波的传播被禁止，而不管空间中的传播方向如何，并定义光子带隙[2，3]。 当与高折射率对比度平板相结合时，光可以被有效地引导，微型二维光子背隙镜为我们提供了将光限制在极小体积内所需的几何形状[4，5]。 在光子带隙结构中引入缺陷，形成了具有微加工反射镜的二维法布里-珀罗谐振腔。 然后，可以通过改变缺陷周围的微结构的精确几何形状来光刻地调谐这些腔。 令人惊讶的是，我们已经发现，在二维光子带隙晶体中由单个缺陷组成的小腔体仍然可以表现出高Q值，并且我们已经通过时域有限差分（FDTD）建模计算出Qs在25，000的范围内[6]。 当在吸收半导体材料中测量真实的空腔时，测得Q值ain excell为1500。 作为我们之前NSF合同的一部分，我们已经表明，这些高Q值现在可以定义在室温下工作的微腔激光器[7][8]，其模体积小至2.5（1/2nslab）3，或InGaAsP中发射1.55 μ m的0.03 μ m 3。

The past rapid emergence of optical microcavity devices, such as Vertical Cavity Surface Emitting Lasers (VCSELs) [1] can be largely attributed to the high precision over the layer thickness control available during semiconductor crystal growth. High reflectivity mirrors can be grown with sub-nanometer accuracy to define high=Q cavities in the vertical dimension. Recently, it has also become possible to microfabricate high reflecti-vity mirrors by creating two- and three-dimensional periodic structures. These periodic "photonic crystals" can be designed to open up frequency bands within which the propagation of electromagnetic waves is forbidden irrespective of the propagation direction in space and define photonic bandgaps [2,3]. When combined with high index contrast slabs in which light can be efficiently guided, microfaricated two-dimensional photonic badgap mirrors provide us wit the geometries needed to confine light into extremely small volumes [4,5]. 2-D Fabry-Perot resonators wit hmicrofabricated mirrors are formed when defects are introduced into the photonic bandgap structure. It is then possible to tune these cavities lithographically by changing the precise geometry of the microstructures surrounding the defects. Surprisingly, we have found that small cavities consisting of single defects in a two-dimensional photonic bandgap crystal can still exhibit high Q values, and we have calculated, by finite-difference time-domain (FDTD) modeling, Qs in the range of 25,000 [6]. When real cavities are measured in absorbing semiconductor material, Q values ain excell of 1500 are measured. We have shown, as part of our previous NSF contract, that these high Qs make it now possible to define microcavity lasers [7] which functio at room temperature [8], with mode volumes as small as 2.5 (l/2nslab)3, or 0.03 um3 in InGaAsP emitting at 1.55 um.