【摘 要】
：
Coherent rainbows can be formed by focusing white-light laser into liquids.They are bilaterally symmetric interfer-ence rings with various shapes.Such interference rings arise from the temperature distribution of the liquid induced by laser heating,i.e.,t
【机 构】
：
State Key Laboratory for Superlattices and Microstructures,Institute of Semiconductors,Chinese Acade
论文部分内容阅读
Coherent rainbows can be formed by focusing white-light laser into liquids.They are bilaterally symmetric interfer-ence 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 an oval 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.
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