1：Experimental Design and Method Selection:

The phase-shifting digital holography technique was applied to measure the base angle of axicons. The method involves recording interference holograms with different phase shifts introduced by a spatial light modulator (SLM).

2：Sample Selection and Data Sources:

Three axicons with base angles of

3：5°, 1°, and 1° were measured. List of Experimental Equipment and Materials:

A laser beam, beam expander, SLM, polarizer, axicon, beam splitter (BS3), and charge coupled device (CCD).

4：Experimental Procedures and Operational Workflow:

A laser beam is split into two beams; one is reflected onto the SLM, and the other passes through the axicon. The two beams are combined and interfered, with results recorded by a CCD.

5：Data Analysis Methods:

The phase distribution was solved using four, five, or eight phase-shifted holograms, with the best results obtained using eight holograms.