Ultra-low threshold and spontaneous emission control in semiconductor microdisk lasers

半导体微盘激光器的超低阈值和自发发射控制

基本信息

批准号：
10450025
负责人：
BABA Toshihiko
金额：
$ 7.3万
依托单位：
Yokohama National University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450025/
关键词：
disk laser GaInAs InP spontaneous emission control threshold less laser cavity QED microcavity spontaneous emission factor whispering gallery mode 無しぎ値レーザ共振器OED 周回モードマイクロディスク半導体レーザ Whispering Galleryモード

项目摘要

We obtained the following achievements on microdisk lasers :1. Ultra-small cavity : The injection lasing was obtained in 2-μm-diameter and 0.2-μm-thickness GaInAsP microdisk. The cavity volume is 0.4 μm^3. Although this value is larger than that achieved in a single defect photonic crystal laser, it is still the smallest for injection lasers. Such a small cavity provides various evidences of the spontaneous emission control.2. Ultra-low threshold : I_<th>=40μA was achieved under cw condition, the lowest record for GaInAsP lasers. The effective J_<th> is 320 A/cm_2 (80 A/cm_2 per QW). Key issues for lower threshold are the reduction in scattering loss caused by the roughness in the microdisk, and the balance between the carrier diffusion and the scattering loss at post edges. A threshold less than 10 μA and internal efficiency higher than 50 % will be possible by the engineering of whispering gallery modes, free carrier absorption, strain relaxation in QWs, etc.3. Fragileness : This wil … More l be a problem in future applications. To satisfy both the mechanical strength and optical confinement, a microdisk buried by the selectively oxidized AlInAs claddings was proposed. The depth and the optical absorption in the oxidized claddings are key issues to be investigated.4. Strong optical confinement : The low threshold is obtained by the total internal reflection at microdisk boundaries, which is unsuitable for light extraction. The evanescent coupling of microdisk elements was investigated by the FDTD simulation. Over 60 % extraction efficiency is expected by the <0.3 μm space between the microdisk elements.5. Evanescent field spreading around the microdisk : This feature can be used in a near field probe sensor. The lasing characteristic is modulated by the surface profile of an object put close to the microdisk. A spatial resolution of 〜λ/10 were expected theoretically and experimentally. The scanning microscopy against metal and dielectric objects was demonstrated by the use of this active probe. Less

我们在微盘激光器上取得了以下成果： 1.超小腔体：在直径为2μm、厚度为0.2μm的GaInAsP微盘上获得了注入激光，腔体体积为0.4μm^3。与单缺陷光子晶体激光器相比，它仍然是最小的注入激光器，提供了超低阈值控制的各种证据。在连续波条件下实现了 I_<th>=40μA，GaInAsP 激光器的最低记录为 320 A/cm_2（每 QW 80 A/cm_2）。降低阈值的关键问题是散射损耗的减少。由微盘的粗糙度引起的，以及载流子扩散和柱边缘的散射损耗之间的平衡，阈值小于10μA，内部效率高于50%。通过回音壁模式、自由载流子吸收、量子阱中的应变弛豫等工程，这将成为未来应用中的一个问题，通过选择性氧化掩埋微盘。提出了AlInAs包层的深度和光吸收是需要研究的关键问题。 4．微盘边界处的反射，不适合光提取。通过 FDTD 模拟研究了微盘元件之间的 <0.3 μm 空间的渐逝耦合，预计其提取效率可达 60% 以上。 5．微盘：此功能可用于近场探针传感器，激光特性由靠近微盘的物体的表面轮廓调制。通过使用这种有源探头，理论上和实验上都预期可以对金属和介电物体进行扫描显微镜检查。