High-precision dispersion fringe sensing via a tilt-robust phase decoupled algorithm

Mitigating the impact of pointing jitter is a prerequisite for achieving high-precision Dispersed Fringe Sensing (DFS) in dynamic environments. This Letter proposes a tilt-robust phase decoupled reconstruction (PDR) method that utilizes the strict vanishing of tip/tilt-induced phase modulation at the spatial carrier-frequency peak. Leveraging this property, the PDR method extracts the tilt-immune piston phase at the carrier peak and employs multi-wavelength least-squares unwrapping to retrieve the absolute piston error. Both numerical simulations and experiments confirm the method's excellent tilt robustness. Specifically, an experimental piston retrieval precision of 0.034 μm RMS is achieved under continuous sinusoidal pointing jitter, demonstrating the method's capability for high-precision co-phasing in future synthetic aperture telescopes.