Double Slit Experiment Still Has Much to Offer (3): Extended-Delayed-Choice Experiments---Supporting Causality

The interpretations of the delayed-choice experiments suggest that photons "retroactively decide" to travel as particles or as wave from the time of its emission. To test the interpretations thoroughly, we propose and perform extended-delayed-choice experiments. The experiments are designed for easier to set up, carry out and reach meaningful results without ambiguous. The experimental results show the following: (A) the causality holds; (B) Bohr's complementarity principle is violated; (C) photons behave as particle before striking at output beam splitter/double-slit/crossdouble-slit; (D) the present does not determine the past retroactively, but determines the future.