Twyman–Green-type integrated laser interferometer array for parallel MEMS testing

Oliva, Maria; Michaelis, Dirk; Dannberg, Peter; Jóźwik, Michał; Liżewski, Kamil; Kujawińska, Małgorzata; Zeitner, Uwe D.

doi:10.1088/0960-1317/22/1/015018

Cited by 10 publications

(4 citation statements)

References 17 publications

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“…The experimental studies of the macroscopic deformation field in SCO materials remains an open issue, although it is well admitted that the SCO phenomenon has an elastic long-range nature. , On the other hand, the optical interferometry (OI) technique is widely recognized as one of the most sensitive techniques allowing optical measurements to track size changes and appearance of cracks in single crystals. − In this paper, we use for the first time the optical interferometry technique combined to OM to reveal the macroscopic deformation of a SCO single crystal during its thermal spin transition. In the literature, experiments using interferometry have mainly concerned the investigations of the mechanical properties of polymers ,− and their behavior as a function of temperature, ,− as well for checking the flatness of surfaces. , It is well known that interferences occur when the light intensity resulting from the superposition of several light waves is different from that of the light waves intensities . The intensity of the IP depends on the phase shift of the different superimposed light waves and requires some particular conditions.…”

Section: Dynamics Of the Spin Transition Revealed By Interference Tec...mentioning

confidence: 99%

Dance of Interference Patterns during the Spin Transition of a Single Crystal

Boukheddaden

2020

J. Phys. Chem. C

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Optical microscopy investigations have allowed the study of the spatiotemporal dynamics of the nucleation, growth, and propagation along with first-order phase transitions in cooperative spin-crossover (SCO) single crystals. They made possible the monitoring of the high-spin (HS)/low-spin (LS) interface and the control of its orientation and its velocity along the transformation process. Up to now, and especially for spin transition materials, all information obtained from this technique was restricted to the 2D area of the crystal's surface, imaged by a camera. In this paper, we present a breakthrough method which allows us to follow the dynamics of the 3D single-crystal deformation during the spin transition. To pursue this objective, we adapted an optical interferometry technique under a microscope, to capture in real-time the images for first-order thermally induced SCO transition on a unique single crystal. The optical interferometry data showed that along the cooling regime, the spin transition proceeds through a nucleation and propagation of a single domain process with an average interface velocity of 0.8 μm/s. In contrast, on the heating regime, the transformation started from the two opposite sides of the crystal and the analysis of their mutual dynamics indicated a clear interplay between them, thus confirming the long-range elastic nature of the spin transition phenomenon. Taking advantage of the high sensitivity of the interferometry technique to the crystal's deformation, we could observe the deformation field of the SCO crystal by monitoring the interface propagation which resulted in an impressive dance of the interference patterns, through their global shift and their distortion. Moreover, optical interference technique was able to detect precursor phenomena of stress-driven long-range effects in the HS and LS phases immediately before the transition, even though that optical microscopy technique was silent in these regions. To understand these observations, a spatiotemporal model has been developed in which we have dissected the complex behavior of the interference fringes, resulting from the volume change (expansion and/or compression) of the crystal in the course of the spin transition.

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Section: Dynamics Of the Spin Transition Revealed By Interference Tec...mentioning

confidence: 99%

Dance of Interference Patterns during the Spin Transition of a Single Crystal

Boukheddaden

2020

J. Phys. Chem. C

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“…This approach uses custom designed diffractive optical elements which are fabricated on two glass substrates requiring precise alignment and bonding process [18]. The top surface of the substrate includes diffractive optical element DOE1 etched on the it.…”

Section: Laser Interferometer Arraymentioning

confidence: 99%

Micro-optics in advanced optical metrology

Jóźwik

2013

SPIE Proceedings

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An accurate characterization is a very important topic in a wide range of MEMS/MOEMS applications and crucial for their fabrication process. Standard characterization is performed with bulk measurement system. Usually, a high resolution optical systems measure one structure at a time and scan the measurement samples from structure to structure. These systems are not well suited to the production control of microsystems, where several thousands of structures are fabricated on the same substrate simultaneously. The paper presents new approaches using microoptics and micromachining to overcome the large ratio of wafer size to feature size in the testing step of production. The refractive and diffractive microoptical components, often fabricated on glass wafer, allow to create arrays of integrated measurement instruments. This work focuses on a new full-field optical concept for parallel, high volume M(O)EMSs' testing. The use of diffraction gratings for the realization of an array of integrated interferometers allows to create compact device with 25 measurement channels. The design of measurement platform and interferometer array, its assembly and the validation measurement results, are discussed in details. The functionality of system includes static and dynamic in-line characterization of MEMS.

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“…A Twyman-Green interferometer is one in which a division of amplitude takes place [28][29][30]. Interference occurs from the recombination of two parts of a beam of light, which is divided by partial reflection and partial transmission at a beam-splitter.…”

Section: Introductionmentioning

confidence: 99%

Laser Velocimetry for the In Situ Sensing of Deep-Sea Hydrothermal Flow Velocity

Sun,

Zhang,

et al. 2023

Sensors

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Laser Doppler velocimetry (LDV) based on a differential laser Doppler system has been widely used in fluid mechanics to measure particle velocity. However, the two outgoing lights must intersect strictly at the measurement position. In cross-interface applications, due to interface effects, two beams of light become easily disjointed. To address the issue, we present a laser velocimeter in a coaxial arrangement consisting of the following components: a single-frequency laser (wavelength λ = 532 nm) and a Twyman–Green interferometer. In contrast to previous LDV systems, a laser velocimeter based on the Twyman–Green interferometer has the advantage of realizing cross-interface measurement. At the same time, the sensitive direction of the instrument can be changed according to the direction of the measured speed. We have developed a 4000 m level laser hydrothermal flow velocity measurement prototype suitable for deep-sea in situ measurement. The system underwent a withstand voltage test at the Qingdao Deep Sea Base, and the signal obtained was normal under a high pressure of 40 MPa. The velocity contrast measurement was carried out at the China Institute of Water Resources and Hydropower Research. The maximum relative error of the measurement was 8.82% when compared with the acoustic Doppler velocimeter at the low-speed range of 0.1–1 m/s. The maximum relative error of the measurement was 1.98% when compared with the nozzle standard velocity system at the high-speed range of 1–7 m/s. Finally, the prototype system was successfully evaluated in the shallow sea in Lingshui, Hainan, with it demonstrating great potential for the in situ measurement of fluid velocity at marine hydrothermal vents.

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Twyman–Green-type integrated laser interferometer array for parallel MEMS testing

Cited by 10 publications

References 17 publications

Dance of Interference Patterns during the Spin Transition of a Single Crystal

Dance of Interference Patterns during the Spin Transition of a Single Crystal

Micro-optics in advanced optical metrology

Laser Velocimetry for the In Situ Sensing of Deep-Sea Hydrothermal Flow Velocity

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