Quasicommon-path digital holographic microscopy with phase aberration compensation based on a long-working distance objective

We present a quasicommon-path digital holographic microscopy with phase aberration compensation, which is based on a long-working distance objective and can be used for the quantitative characterization of microstructure specimens. The quasicommon-path arrangement makes the holographic system very compact and stable. Meanwhile, the object and reference beams all travel along the same path, which can effectively eliminate the system aberration, and the mirror in the reference arm can be adjusted precisely for the phase tilt compensation. In the experiment, a wafer with orderly patterns and unified height of 180 nm is measured, and its three-dimensional surface topography is obtained. A long-term system stability of 1.39 nm is achieved in measurement with the proposed method.