Circular polarized light-differential interference contrast (C-DIC) is a new polarization-optical differential interference contrast method where, unlike conventional DIC according to Nomarski [Interferometre A polarisation, French Patent 1.059.123, 1952.], the DIC prism (DP) is arranged in circular, not linear, polarized light. Consequently, the interference contrast generated is invariant in relation to the oscillation orientation of the DIC prism, and so the latter can be rotated directionally in accordance with the characteristics of the object. This means that the stage does not need to be rotated while the relationship with the object is preserved. For the user, this means more information and an increase in sample throughput. (C) 2004 Elsevier B.V. All rights reserved.