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New theories of light have been derived from optical interference, and it has also been used in interferometry for the measurement of small displacements. The fringes of light can be easily observed with the help of the Michelson interferometer. The interferometer has been used in many famous physical experiments.
A team of scientists led by Professor Bao-Sen Shi and associate professor Zhi-Yuan Zhou from the University of Science and Technology of China have demonstrated a special equal-inclination interference by using non-.
The photon used in the interferometer is generated by a pump photon in a second-order crystal, which splits into a pair of lower-energy photon with a certain probability. The interference is related to the special spectrum of photons generated from the SPDC process. The principle of interference is that the frequencies different from the crystal have different divergence angles, and each divergence angle corresponds to a unique frequency combination, and finally have different results of constructive or destructive interference. The interference is caused by a combination of interference patterns of different components.
The principle and phenomenon of the ASD interference are similar to those of the traditional equal-inclination interference: They both have ring-like fringes, the phase difference inducing bright or dark rings is dependent on the angle, and the number of rings is dependent on OPD. Under their experimental conditions, is related to the interference fringes with different arm differences. The phenomenon can be measured using an equivalent wavelength, which is about 1/27 of the real wavelength. The physical meaning of the equivalent wavelength is that the interference fringes are the same as those from a traditional equal-inclination interferometer in which the wavelength of the photons has this value. The paper shows that the parameters can be improved by adjusting the experimental parameters.
The advantage of the interference is that it can be used to measure small displacements or Refractive index changes, which can be used to improve the sensitivity for OpD. The point at which the zero OPD can be determined more accurately is the point at which the optical path measurement accuracy can be improved.
Light: Science & Applications has more information about Chen Yang et al. The DOI is 10.1038/s41377-021-00661-z.
Light: Science and Applications is the journal's information.
The research team demonstrates interference on December 27th, 2021.
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