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余弦高斯光束焦點(diǎn)區域光強分布和焦深的影響。 - 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(huán)的外半徑，焦深沿軸向變大，相位板可以調節光學(xué)焦深，并且可調的范圍很大。
