Author(s): Shi, TT (Shi, Tingting); Qian, X (Qian, Xuan); Sun, TJ (Sun, Tianjiao); Cheng, L (Cheng, Li); Dou, RJ (Dou, Runjiang); Liu, LY (Liu, Liyuan); Ji, Y (Ji, Yang)

Source: CHINESE PHYSICS B Volume: 30 Issue: 12 Article Number: 124208 DOI: 10.1088/1674-1056/ac0039 Published: DEC 2021

Abstract: Coherent rainbows can be formed by focusing white-light laser into liquids. They are bilaterally symmetric interference rings with various shapes. Such interference rings arise from the temperature distribution of the liquid induced by laser heating, i.e., thermal lens effect, which changes the refractive index locally and thus the optical path difference. The up-down asymmetry of the interference rings is caused by convection in the liquid. With the increase of the viscosity, the interference rings change their shape from oval to circular shape. After a shutter is opened and the laser shines into the liquid, the interference rings are circular at the beginning. As time goes on, they gradually turn into anoval shape. Let the liquid go a free-fall at the beginning, the interference rings remain circular. All the three experiments have confirmed that the asymmetric interference rings are due to convection in the liquid associated with thermal lens effect. We also numerically simulate the two-dimensional heat conduction with and without convection, whose results agree well with our experimental observations.

Accession Number: WOS:000733605800001

ISSN: 1674-1056

eISSN: 2058-3834

Full Text: https://iopscience.iop.org/article/10.1088/1674-1056/ac0039