基于有效折射率法建立了窄脊型波导数值计算模型，通过实验研究了InGaAs量子阱窄脊型波导半导体激光器偏振特性与横模之间的关系。根据理论计算，脊型波导中类TM模式在慢轴方向的有效折射率差更大，类TM模式的限制因子比类TE模式的限制因子更大、更容易出现慢轴高阶模式；而随着脊型波导的高度增加，快轴高阶模式被截断，类TE₀₀模式的限制因子逐渐增加至与类TM₀₀模式相近，慢轴高阶模式因其大的散射损耗被抑制，理论上可实现高偏振度、高光束质量激光输出。在实验方面，利用量子阱材料的增益偏振特性，通过脊型高度与宽度的设计，制备了高偏振度、基横模的窄脊型波导半导体激光器。

We propose to generate a sub-nanometer-confined optical field in a nanoslit waveguiding mode in a coupled nanowire pair (CNP). We show that, when a conventional waveguide mode with a proper polarization is evanescently coupled into a properly designed CNP with a central nanoslit, it can be efficiently channeled into a high-purity nanoslit mode within a waveguiding length <10 μm. The CNP can be either freestanding or on-chip by using a tapered fiber or planar waveguide for input-coupling, with a coupling efficiency up to 95%. Within the slit region, the output diffraction-limited nanoslit mode offers an extremely confined optical field (∼0.3 nm × 3.3 nm) with a peak-to-background ratio higher than 25 dB and can be operated within a 200-nm bandwidth. The group velocity dispersion of the nanoslit mode for ultrafast pulsed operation is also briefly investigated. Compared with the previous lasing configuration, the waveguiding scheme demonstrated here is not only simple and straightforward in structural design but is also much flexible and versatile in operation. Therefore, the waveguiding scheme we show here may offer an efficient and flexible platform for exploring light–matter interactions beyond the nanometer scale, and developing optical technologies ranging from superresolution nanoscopy and atom/molecule manipulation to ultra-sensitivity detection.

高性能材料研究使有机发光二极管（Organic light?emitting diode，OLED）取得了突飞猛进的发展，但是器件内部生成的光子由于光学损耗无法全部发射到外部空间，从而极大地降低了OLED效率，并阻碍了其在节能照明市场的应用。通过调控光损失区域的波传导，光提取技术能够有效抑制衬底、波导、表面等离子激元等损耗模式，理论上可使效率扩大4倍。具有1.05~2倍扩大效果的光提取技术已被大量报道，但与理论极限仍存在很大差距。为此，本文简要分析了OLED光学损耗模式，综述了近年来高效的、特别是能实现2倍以上扩大效果的光提取技术。