The predicted extraordinary properties of carbon nanotubes(CNTs)from theoretical calculations have great potential for many applications.However,reliable experimental determination of intrinsic properties at the single-tube level is currently a matter of concern,and many challenges remain because of the unhandled and nanoscale size of individual nanotubes.Here,we demonstrated a prototype to detect the intrinsic thermal conductivity of the single-wall carbon nanotube(SWCNT)and verify the significant non-resonant optical absorption behavior on tiny nanotubes by integrating the nanotube and ice into a new core-shell design.In particular,a reversible optical visualization method based on the individual suspended ultra-long SWCNT was first developed by wrapping a nanotube with ice in the cryogenic air environment.The light-induced thermal effect on the hybrid core-shell structure was used tomelt the ice shell,which subsequently acted as a temperature sensor to verify the intrinsic thermal conductivity of the core-like nanotube.More interestingly,we successfully determined for the first time the thermal response phenomenon of the tiny absorption cross section in SWCNT in the vertical-polarization configuration and the significant non-resonant absorption behavior in the parallel-polarization configuration.These investigations will provide a better understanding for the unique optical behaviors of CNT and enable the detection of intrinsic properties of various one-dimensional nanostructures such as nanotubes,nanowires,and nanoribbons.