A two-beam interferometer is proposed and experimentally demonstrated with OPD magnified. Two cascaded fiber ring resonators with almost the same fiber length are spliced into a fiber loop. An acousto-optic modulator is employed to generate optical pulses and to choose the pulses traveling around one of the resonators for x trips. The interferometer is characterized in displacement in our experiment. Experimental results show the proportional relationship between the sensitivity and x. The high-sensitivity interferometer scheme is useful in some measurement applications that require high sensitivity, such as solid earth tide gauge.
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http://dx.doi.org/10.1364/OL.38.000133 | DOI Listing |
Homodyne demodulation using a phase-generated carrier (PGC) has been applied in fiber-optic interferometric sensors to overcome the signal fading and distortion due to the drift of the operating point. An assumption needed for the PGC method to be valid is that the sensor output is a sinusoidal function of the phase delay between the arms of the interferometer, which is readily achieved by a two-beam interferometer. In this work, we theoretically and experimentally study the effect of three-beam interference, whose output deviates from a sinusoidal function of the phase delay, on the performance of the PGC scheme.
View Article and Find Full Text PDFMaterials (Basel)
October 2022
Department of Thermal Physics and Technical Physics, Al-Farabi Kazakh National University, Al-Farabi Av. 71, Almaty 050040, Kazakhstan.
The interaction of host molecules with water molecules is of primary importance in astrophysical and atmospheric studies. Water-binding interactions continue to attract a broad interest in various fields, especially those related to the formation of assembly structures. Using the physical vapor deposition (PVD) method and a two-beam interferometer with a wavelength of 406 nm, the refractive indices of thin films of a water and nitrogen (argon) mixture were calculated in the range from 15 to 35 K.
View Article and Find Full Text PDFRev Sci Instrum
September 2022
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, China.
An in-fiber Michelson interferometric sensor was presented by fabricating a concavity on the end face of a single mode fiber using a single CO laser pulse. Reflected beams from the bottom and air-cladding boundary of the concavity are coupled into the fiber core and superimpose to generate a two-beam in-fiber Michelson interferometer. Compared with other laser-machining methods where multiple scanning cycles with precise manipulation are needed, the proposed method is more straightforward because only a single laser pulse is used to construct the sensor.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
March 2022
Institute of Low Temperature Science, Hokkaido University, Kita-ku, Sapporo 060-0819, Japan.
SignificanceStep-bunching instability (SBI) is one of the interfacial instabilities driven by self-organization of elementary step flow associated with crystal-growth dynamics, which has been observed in diverse crystalline materials. However, despite theoretical suggestions of its presence, no direct observations of SBI for simple melt growth have been achieved so far. Here, with the aid of a type of optical microscope and its combination with a two-beam interferometer, we realized quantitative in situ observations of the spatiotemporal dynamics of the SBI.
View Article and Find Full Text PDFLight Sci Appl
October 2021
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui, China.
Optical interference is not only a fundamental phenomenon that has enabled new theories of light to be derived but it has also been used in interferometry for the measurement of small displacements, refractive index changes, and surface irregularities. In a two-beam interferometer, variations in the interference fringes are used as a diagnostic for anything that causes the optical path difference (OPD) to change; therefore, for a specified OPD, greater variation in the fringes indicates better measurement sensitivity. Here, we introduce and experimentally validate an interesting optical interference phenomenon that uses photons with a structured frequency-angular spectrum, which are generated from a spontaneous parametric down-conversion process in a nonlinear crystal.
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