可撓式光子晶體奈米柱雷射

Abstract

近年來，微觀尺度的光子晶體結構在各種光學應用上已被大量發展，而應用於積體光路上的雷射光源為其中之一門重要課題，藉由微調光子晶體的幾何結構參數，可得到特定的操作波段以及操作模態。然而，一旦光子晶體的結構製作完成，雷射光波長便已決定而難以改變，而另一方面，以軟性有機材料製作的光學元件有較高的應用性以及低成本等優點。於是我們結合了光子晶體的高密度整合特性與軟性材料的應用適應性等優點於我們的光學元件上，在本篇論文當中，我們展現了以磷砷化銦鎵奈米柱製作於聚二甲基矽氧烷基板上的可撓式光子晶體奈米柱雷射。此類磷砷化銦鎵奈米柱包含了四層增益峰值設計於1.55微米光通訊波長的量子井結構，並且我們在1.55微米波段附近觀察到了位於高對稱Г點上的能帶邊緣型雷射現象。可撓式雷射的優點之一是光學特性可藉由微調結構參數而改變，我們觀察到了經由增加光子晶體晶格的拉升比例，可輕易的控制雷射光波長的位置。當晶格拉升比例由零提升至8.88百分比時，我們可以得到大約26.4奈米的近似線性紅移現象，大約是每變動一個晶格百分比時即可獲得3奈米的波長變化。如此幾何結構可微調的特性指出了可撓性光子晶體雷射在積體光路的應用中可作為高密度整合的可調諧光源。

In recent years, the micro-scale photonic crystal structures have been developed for a variety of optical applications. One of the important topics is the compact laser light source in the photonic integrated circuit. Specific wavelengths and operation modes for applications could be achieved by fine-tuning the geometry of the photonic crystal structure. However, the lasing wavelength would hard to be altered once the laser structure was fabricated. On the other hand, the organic/polymer based devices have advantages such as application flexibility and low cost. We combine the features of compactness in photonic crystal and flexibility in flexible materials. In this thesis, a flexible photonic crystal nanorods laser was demonstrated with InGaAsP nanorods on a polydimethylsiloxane (PDMS) substrate. The InGaAsP nanorods content 4 quantum wells which are designed for 1.55 μm communication wavelength. The lasing action was observed around 1550nm which is a band-edge emission at high-symmetry Γ-point of photonic crystals. One of advantages of the flexible laser is the fine-tuning of optical properties by manipulating its geometry. In this work, we observed the lasing wavelength can be controlled by increasing photonic crystal lattice extension. The lasing wavelength was linearly red-shift up to 26.4 nm as the lattice extension percentage increased to 8.88 %. The wavelength tuning rate is approximately 3 nm for 1 % lattice extension. Those geometric fine-tuning properties indicate the flexible photonic crystal laser can be applied as a compact tunable light source in photonic crystal integrated circuits.