“通常情况下，除了超晶格活跃区域，量子级联激光器设计只有一个高能态，”论文第一作者藤田一惠（Kazuue Fujita）在电子邮件采访中告诉PhysOrg.com。

“Usually, quantum cascade laser designs have only one upper state, except for superlattice active region, ” Kazuue Fujita, the lead author on the paper, tells PhysOrg.com in an email interview.

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他注意到一幢新楼正在惠特克公园附近拔地而起。

He noticed a new building going up near Whitaker Park.

《柯林斯英汉双解大词典》

这是所付的一笔特惠款。

The sum was paid ex gratia.

《牛津词典》