Description
We present an improved continuous phase-shifting digital holography method for micro-object imaging based on a dual-reference configuration. The proposed technique extends continuous phase-shifting holography [1] and follows the general Fourier-transform spectrometry principle underlying hyperspectral holography [2].
In the proposed scheme, a diffraction grating generates two first diffraction orders, which serve as reference waves, while the zero diffraction order illuminates the object. During acquisition, the grating is translated, producing continuous phase modulation and enabling the recording of a sequence of interferograms. It is shown that the fundamental modulation frequency carries information about the complex field of the object, whereas the second harmonic contains information about the modulation phase itself.
In post-processing, the phase trajectory ϕ(t) is extracted from the second harmonic component and used to correct the interferometric signal at the fundamental frequency. This correction compensates for nonuniform phase shifts, mechanical instability, and environmental perturbations without requiring active feedback control or a separate phase-monitoring channel. The method is also considered for recording dynamic micro-objects whose intrinsic phase varies slowly compared with the imposed modulation, allowing object dynamics to be separated from the phase-shifting trajectory.
As a result, the corrected holographic signal demonstrates improved coherence and stronger spectral localization, enabling more reliable recovery of the complex object field under non-ideal experimental conditions.
[1] Sergey G. Kalenkov, Georgy S. Kalenkov, and Alexander E. Shtanko, "Continuous phase-shifting holography," J. Opt. Soc. Am. A 37, 39-44 (2020)
[2] S. G. Kalenkov, G. S. Kalenkov, and A. E. Shtanko, "Hyperspectral holography: an alternative application of the Fourier transform spectrometer," J. Opt. Soc. Am. B 34, B49-B55 (2017)
| I am the presenting author | Yes |
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