Dan LIU¹, An Lian PAN³, Gengzhao XU¹, Yongqiang BAI¹, Xing ZHU^1,2,* and Bing Suo ZOU³

¹State Key Lab for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
²National Center for Nanoscience and Nanotechnology, Beijing 100080, China
³Nanoscale Physics & Device Lab, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China

(Received November 15, 2005; Accepted May 11, 2006)

Scanning near-field optical microscopy (SNOM) and spectroscopy were used to study the light emission characteristics of CdS nano-ribbon optical waveguide. A continuous red-shift of photoluminescence (PL) spectra of such nano-ribbons with the increase of the light propagation distance was observed. Near-field optical images indicate that CdS nano-ribbon can work well as an optical waveguide. Quantitative calculation was made to demonstrate the PL attenuation with long propagation distance (typically several hundreds μm). The red shift is attributed to self-absorption, which means re-absorption and re-emission among energy-valleys with different energies of conduction bands. Our results draw attention to the spectral characteristics of nano-ribbon optical waveguides, which are as important as intensity to the stability and veracity of information transmission.

Key words: near-field optics, nano-optics, optical waveguide, semiconductor, photoluminescence (PL)

^*Corresponding author. E-mail address: zhuxing@pku.edu.cn