depth of focusing的用法和樣例：
例句
- Focal depth of hyperbolic-cosine-Gaussian beams induced by a phase plate was investigated.
摘要研究了同軸分區相位板對雙曲餘弦高斯光束焦點區域光強分佈和焦深的影響。 - There are two critical values for outer radius of the inner annular zone, at which focal spot changes sharply.The tunable range of the focal depth is very considerably.
增大內圓環的外半徑，焦深沿軸向變大，相位板可以調節光學焦深，並且可調的範圍很大。
