Rather than fine-tune metamaterial to exact specifications, which is finicky and expensive, the researchers used nanoparticles of cobalt, which are relatively easy to get hold of, and suspended them in kerosene.
研究者并没有对超材料具体规格进行微调,因为这样既繁杂又增加成本,他们使用了钴纳米粒子,这个相对而言容易得到,可以把它们暂时存放在煤油中。