Time-of-flight method using multiple pulse train interference as a time recorder.

A unique length measurement method, called the multiple pulse train interference-based time-of-flight (TOF) method, is proposed and demonstrated for the first time. By taking advantage of both the high-accuracy measurement capability of a pulse train interference method and the arbitrary and absolute length measurement capability of a TOF method, the present method is expected to be useful for high-precision length measurement for not only science purposes but also industry requirements. A long gauge block was measured using this optical method to demonstrate the feasibility of the proposed method.