Topic
Interferometry
About: Interferometry is a research topic. Over the lifetime, 58031 publications have been published within this topic receiving 824872 citations.
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TL;DR: In this article, an in-fiber hybrid modal interferometer (HMI) is theoretically and experimentally demonstrated in a section of bias-tapered multimode fiber only fabricated by arc-discharge technique, which consists of multimode interferometers (MMI) and Mach-Zehnder interferers (MZI).
Abstract: An in-fiber hybrid modal interferometer (HMI) is theoretically and experimentally demonstrated in a section of bias-tapered multimode fiber only fabricated by arc-discharge technique, which consists of multimode interferometer (MMI) and Mach-Zehnder interferometer (MZI). The MZI has the sensitivity as high as −31.08 nm/RIU, but the MMI presents the immunity of both wavelength and intensity to ambient refractive index (RI). In strain test, MMI has a 9.8-dB intensity deduction and MZI shows high wavelength sensitivity (−6.31 pm/ $\mu \varepsilon$ ). Thus, our HMI shows a strong multi-parameter discriminative proficiency and simultaneous measurement of RI, strain and temperature is achieved by the means of joint wavelength and intensity demodulation-based inversion-matrix method. Such a compact and low-cost sensor, without the crosstalk from the temperature and the light source, is very promising for the applications of biochemical sensing and structural health monitoring.
20 citations
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TL;DR: In this paper, the amplitude calibration of two-dimensional nanomechanical resonators is performed without any knowledge of the device parameters such as its mass, actuation force, geometric distances, or laser intensity.
Abstract: Contactless characterization of mechanical resonances using Fabry-Perot interferometry is a powerful tool to study the mechanical and dynamical properties of atomically thin membranes. However, amplitude calibration is often not performed or only possible by making assumptions on the device parameters such as its mass or the temperature. In this work, we demonstrate a calibration technique that directly measures the oscillation amplitude by detecting higher harmonics that arise from nonlinearities in the optical transduction. Employing this technique, we calibrate the resonance amplitude of two-dimensional nanomechanical resonators, without requiring knowledge of their mechanical properties, actuation force, geometric distances, or the laser intensity.
20 citations
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TL;DR: In this paper, it was shown that a time-dependent sound speed for the helicity-2 modes can generate primordial gravitational waves with a blue-tilted spectrum, potentially detectable at interferometer scales.
Abstract: With an energy scale that can be as high as $10^{14}\,{\rm GeV}$, inflation may provide a unique probe of high-energy physics. Both scalar and tensor fluctuations generated during this early accelerated expansion contain crucial information about the particle content of the primordial universe. The advent of ground- and space-based interferometers enables us to probe primordial physics at length-scales much smaller than those corresponding to current CMB constraints. One key prediction of single-field slow-roll inflation is a red-tilted gravitational wave spectrum, currently inaccessible at interferometer scales. Interferometers probe directly inflationary physics that deviates from the minimal scenario and in particular additional particle content with sizeable couplings to the inflaton field. We adopt here an effective description for such fields and focus on the case of extra spin-2 fields. We find that a time-dependent sound speed for the helicity-2 modes can generate primordial gravitational waves with a blue-tilted spectrum, potentially detectable at interferometer scales.
20 citations
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TL;DR: In this article, the phase shift and contrast of a double-well Ramsey interferometer were derived in the presence of a gravity or an acceleration field, assuming that the splitting and recombination processes are adiabatic.
Abstract: We report a theoretical study of a double-well Ramsey interferometer using internal state labelling. We consider the use of a thermal ensemble of cold atoms rather than a Bose–Einstein condensate to minimise the effects of atomic interactions. To maintain a satisfactory level of coherence in this case, a high degree of symmetry is required between the two arms of the interferometer. Assuming that the splitting and recombination processes are adiabatic, we theoretically derive the phase-shift and the contrast of such an interferometer in the presence of a gravity or an acceleration field. We also consider using a 'shortcut to adiabaticity' protocol to speed up the splitting process and discuss how such a procedure affects the phase shift and contrast. We find that the two procedures lead to phase-shifts of the same form.
20 citations
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TL;DR: An integrated structure in the original single mode fiber (SMF) which can measure curvature and temperature simultaneously, is proposed and demonstrated in this article, where the curvature sensing of the device is based on the wavelength shift of the MZI interference fringe dips.
Abstract: An integrated structure in the original single mode fiber (SMF) which can measure curvature and temperature simultaneously, is proposed and demonstrated The key components of the device include an in-fiber Mach–Zehnder interferometer (MZI) and a fiber Bragg grating (FBG), which are integrally fabricated in a coating-unstripped SMF by femtosecond laser direct writing The curvature sensing of the device is based on the wavelength shift of the MZI interference fringe dips It is found that the bending response is closely related to the bending orientation The measured curvature sensitivities are 2324 and 2491 nm/m−1 for the 0° and 180° orientation in the range of 0–10 m−1, respectively Under different bending states, the temperature response of the FBG resonant wavelength is almost the same and the mean temperature sensitivity is 972 pm/° The advantages of compact, simple fabrication, low insertion loss, no assembly, wide operating range of curvature measurement and real-time temperature sensing make our device very attractive in practical engineering monitoring and somatosensory posture recognition
20 citations