Chiral microstructures (spirals) fabrication by holographic lithography
  We present an optical interference model to create chiral microstructures (spirals) and its realization in photoresist using holographic lithography. The model is based on the interference of six equally-spaced circumpolar linear polarized side beams and a circular polarized central beam. The pitch and separation of the spirals can be varied by changing the angle between the side beams and the central beam. The realization of the model is carried out using the 325 nm line of a He-Cd laser and spirals of sub-micron size are fabricated in photoresist. 
Yee Kwong Pang, Jeffrey Chi Wai Lee, Hung Fai Lee, Wing Yim Tam, C. T.   Chan, and Ping Sheng