▎ 摘　　要

We have investigated the temperature evolution (100-300K) of the 2D mode of isotopically labelled double layer graphene using in situ Raman spectro-microscopy. The strain values obtained from the 2D mode analysis were confronted with those obtained from the correlation analysis of the G and 2D modes. We find that the strain landscape derived from the 2D mode is comparable with the one obtained from the G and 2D modes with similar temperature evolution for both layers. However; the magnitude of the strain evaluated by the two different approaches does not fully coincide, which can be attributed to the admixture of uniaxial strain to the dominant biaxial component. In addition, we observed that the 2D is also sensitive to the strain inhomogeneities at nanometre scale. The 2D mode thus serves as a valuable complementary tool for detection of the character of strain in single and double layer graphene down to helium temperatures.