Visualization technique

Images presented in this document were obtained with the light sheet located immediately below the top of the cell. Images were acquired by a 3-CCD color video camera coupled with a framegrabber. The resolution of the framegrabber was 512 by 512 24-bit pixels.

To visualize the temperature field in the illuminated section of the cell, microcapsules filled with thermochromic liquid crystals (TLC) were added to the water filling the cell. The volume ratio of the TLC microcapsules to water was 1:10,000 and the mean size of the capsules 5 microns. TLCs selectively reflect incident white light. Within the range of temperatures corresponding to the existence of the cholesteric phase of the liquid crystal, the wavelength of the reflected light depends monotonically on the temperature. The top and bottom temperatures of the cell were adjusted to match the range of color play of the TLC. Thus the hue component of pixel color in the recorded images can be resolved to temperature, and the temperature field can be reconstructed.