Phase-shifts nπ/2 calibration method for phase-stepping interferometry

Bai, Fuzhong; Rao, Changhui

doi:10.1364/oe.17.016861

Cited by 22 publications

(9 citation statements)

References 10 publications

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“…While all of these latter instruments have been able to track fringes while scanning at upwards of 500 Hz, none of them have addressed the issue of the fringe smear and ultimately the decrease in sensitivity incurred by integrating the fringe signal during the scanning motion. Much effort has gone into characterizing the biases and signal-to-noise ratio penalties incurred when using continuous motion [19], and other studies have focused on the impact of nonlinearities seen when operating PZTs [20,21]. However, it would clearly be beneficial if discrete and fast phase stepping were possible in a temporally modulated instrument.…”

Section: Stellar Interferometers and Phase Shifting Interferometrymentioning

confidence: 99%

Open-loop phase shifting for fast acquisition of interferograms in low light levels

et al. 2013

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Phase shifting interferometry relies on sets of interferograms taken at multiple known phase offsets to deduce the instantaneous phase of a quasi-static fringe pattern. The traditional method for introducing these phase shifts has been either to step a mirror, and measure the fringe pattern at each step, or to scan a mirror, integrating the fringe pattern for discrete time intervals while the fringes "move" on the detector. A stepping mirror eliminates this fringe smear but has typically required a closed-loop controller to ensure that the optical path introduced is accurately known. Furthermore, implementing rapid stepping of a moderately sized optic can prove difficult if the fringe phase needs to be measured on a short time scale. We report results demonstrating very fast (>100 Hz) and precise phase shifting using a piezomodulated mirror operated in open-loop without any position feedback. Our method exploits the use of a synthetic driving waveform that is optimized to match the complex frequency response of the modulator and its supported optic. For phase measurements in the near-infrared at 2.15 μm, and with a time between steps as small as 0.2 ms, we report errors below λ/100 in the desired position of our optic, i.e., an effective optical path difference error of ~λ/55. For applications in near-infrared stellar interferometry, this implies an enhancement in the fringe-tracking sensitivity of roughly 20% (in the photon-limited regime) over that which is conventionally realized using a swept mirror.

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Section: Stellar Interferometers and Phase Shifting Interferometrymentioning

confidence: 99%

Open-loop phase shifting for fast acquisition of interferograms in low light levels

et al. 2013

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“…Phase-shifting interferometry [1,2,3,4,5] is generally used for the interferometric optical testing, especially in Fizeau interferometers. The phase difference is made between two interfering beams and the object phase can be retrieved from a series of interferograms using a suitable algorithm.…”

Section: Introductionmentioning

confidence: 99%

Piezoelectric Actuated Phase Shifter Based on External Laser Interferometer: Design, Control and Experimental Validation

Wang

Sui

et al. 2017

Sensors

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To improve the phase-shifting accuracy, this paper presents a novel integrated framework for design, control and experimental validation of the piezoelectric actuated phase shifter with a trade-off between accuracy and cost. The piezoelectric actuators with built-in sensors are adopted to drive the double parallel four-bar linkage flexure hinge-based mechanisms. Three mechanisms form the tripod structure of the assembled phase shifter. Then, a semi-closed loop controller with inner feedback and outer feedforward loops via the external laser interferometer is developed for accurate positioning of the phase shifter. Finally, experiments related with travel range, step response, linearity and repeatability are carried out. The linearity error is 0.21% and the repeatability error of 10 μm displacement is 3 nm. The results clearly demonstrate the good performance of the developed phase shifter and the feasibility of the proposed integrated framework.

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“…The phase shifting interferometry can be divided into the traditional phase-shifting interferometry [3] and the wavelength-shifting interferometry according to the different ways of phase shifting. Phase shifting method usually can be divided into time and space phase shift.Phase extraction method of frequency domain phase-shifting has a high precision, but the realization of the phase shift by PZT would bring large nonlinear phase shifting error,and it can not work in the complex environment.Spatial phase shifting method has a low environmental stability requirements, it can avoid the problem of nonlinear errors.But its requirements of different part detector need to be in the same context.…”

Section: Introductionmentioning

confidence: 99%

Study on phase demodulation technique with fast and high accuracy for interference fringe pattern

Liu

Tian

Wang³

et al. 2015

SPIE Proceedings

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Due to environmental interference and atmospheric disturbance and other factors, the interference fringes are always drifting. So, the traditional hardware phase shift could not meet the high accuracy demodulation of interference. In this paper, virtual phase shift based on moiré fringes are introduced to realize the phase demodulation of interference fringe.The virtual digital phase shifting interference fringes are generated by computer, and superposed with tested interference fringe to generate phase shifting moire fringe, which are processed through applying phase shift demodulation techniques and the Fourior transform then to obtain the phase information tested. To verify the technique here, a specific experiment for a diameter of 50mm flat optics is executed, and the experimental result is compared with ZYGO-verifire PE interferometer. Our method eliminates the nonlinear error of the hardware phase shifter while improving the processing accuracy, and especially suitable for high-precision testing for optical component with complex environment or for large-aperture optical component, or even the system greatly simplifies the structure of interferometer.

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Phase-shifts nπ/2 calibration method for phase-stepping interferometry

Cited by 22 publications

References 10 publications

Open-loop phase shifting for fast acquisition of interferograms in low light levels

Open-loop phase shifting for fast acquisition of interferograms in low light levels

Piezoelectric Actuated Phase Shifter Based on External Laser Interferometer: Design, Control and Experimental Validation

Study on phase demodulation technique with fast and high accuracy for interference fringe pattern

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