The time evolution of scattering images of PSNPs from immediately after laser irradiation to 120 seconds is shown in Fig. (These image sequences can be seen in the supporting information Video S1.). The laser is irradiated at the center of each image. The measured laser power at the sample position was 62.2 mW. At t = 0 s in Fig. , individual PSNPs are randomly distributed within the camera's field of view. Observing the images from Figs. , it is clear that over time, the PSNPs gradually diffuse away from the central laser spot. This behavior is evidently due to "thermophobic motion," a phenomenon in thermophoresis where particles move from the hotter region to the cooler one. On the other hand, as seen in Figs. 6d to -g, during the period from 60 seconds to 120 seconds, PSNPs within a radius of approximately 20 μm from the laser spot are excluded due to thermophoresis. The spatial distribution of PSNPs after 60 seconds appears to be in a steady state. This black-hole-like distribution of PSNPs closely matches the thermophoretic depletion observed in previous studies. Prior literature also reports that thermophoretic depletion dynamics occur on the timescale of tens of seconds to about a minute after laser irradiation, induced by solvent heating from a focused laser, with the system reaching a steady state as long as the laser continues to irradiate. Therefore, it can be concluded that thermophoresis is clearly observed in our experimental system, as demonstrated in Fig. , by heating water with the laser. In other words, the dominant observation of thermophoresis suggests that natural convection is suppressed, and the contribution of optical trapping due to radiation pressure is also minor contribution.