  Chiral materials have attracted significant research interests as they
exhibit intriguing physical properties, such as chiral optical response,
spin-momentum locking and chiral induced spin selectivity. Recently, layered
transition metal dichalcogenide 1T-TaS2 has been found to host a chiral charge
density wave (CDW) order. Nevertheless, the physical consequences of the chiral
order, for example, in electronic structures and the optical properties, are
yet to be explored. Here, we report the spectroscopic visualization of an
emergent chiral electronic band structure in the CDW phase, characterized by
windmill-shape Fermi surfaces. We uncover a remarkable chirality-dependent
circularly polarized Raman response due to the salient chiral symmetry of CDW,
although the ordinary circular dichroism vanishes. Chiral Fermi surfaces and
anomalous Raman responses coincide with the CDW transition, proving their
lattice origin. Our work paves a path to manipulate the chiral electronic and
optical properties in two-dimensional materials and explore applications in
polarization optics and spintronics.
