Optical pulse generation with programmable positions in an actively mode-locked optical cavity.

A novel, to our knowledge, approach for generating optical pulses with programmable positions in an actively mode-locked (AML) optical cavity is proposed and experimentally demonstrated. In the AML, active mode locking occurs when the cavity gain exceeds one, and the cavity round trip time equals integer multiples of the repetition period of the electrical driving signal. The generated optical pulses are present at the positions where the optical cavity operates at its maximum transmission points.

Two-frame random phase-shifting interferometry immune to the influence of tilted phase-shift.

To expand the reliability of interferometry technology, this paper proposes a random two-frame algorithm with high accuracy, high robustness, and immunity to tilt phase-shift. This method uses the equivalence of inter-frame phase-shift and intra-frame phase difference to mine light intensity pixels carrying new phase-shift from different images. Then, the linear random phase-shift plane is fitted by least squares, and the inverse tangent relationship is used to obtain a high-precision phase distribution.

Fast and precise single-frame phase demodulation interferometry.

To achieve real-time phase detection, this paper presents a fast and precise spatial carrier phase-shifting interferometry based on the dynamic mode decomposition strategy. The algorithm initially produces a series of phase-shifted sub-interferograms with the aid of a spatial carrier interferogram. Subsequently, the measured phases are derived with great accuracy from these sub-interferograms through the use of the dynamic mode decomposition strategy, an outstanding non-iterative algorithm.