Azimuthal Walsh Filters : A Tool to Produce 2D and 3D Light Structures

This book explores the possibility of using azimuthal Walsh filters as an effective tool for manipulating far-field diffraction characteristics near the focal plane of rotationally symmetric imaging systems. It discusses the generation and synthesis of azimuthal Walsh filters, and explores the inherent self-similarity presented in various orders of these filters, classifying them into self-similar groups and sub-groups. Further, it demonstrates that azimuthal Walsh filters possess a unique rotational self-similarity exhibited among adjacent orders. Serving as an atlas of diffraction phenomena with pupil functions represented by azimuthal Walsh filters of different orders, this book describes how orthogonality and self-similarity of these filters could be harnessed to sculpture 2D and 3D light distributions near the focus. 

Dr. Indrani Bhattacharya is a Post-doctoral researcher associated with Prof. Ayan Banerjee of Light Matter Interaction Lab, Indian Institute of Science Education and Research, IISER, Kolkata and Prof. Vasudevan Lakshminarayanan of School of Optometry, University of Waterloo, Canada. She obtained her Ph.D. from the Department of Applied Optics and Photonics, University of Calcutta. Dr. Bhattacharya is having 20 years industry and 9 years of academic experience. Her research areas include Diffractive Optics, Biomimetics, Optical Tweezers, Point Spread Function Engineering, In-Vivo and In-Vitro Biomedical Applications, Optical Fibre Sensors. She is a member of Optical Society of India, International Society of Optics and Photonics, International Society of Optomechatronics.

Prof. Lakshminarayan Hazra has over four decades of academic and industrial experience. He is an Emeritus Professor and Former Head of the Department of Applied Optics and Photonics at the University of Calcutta, Kolkata, India. His areas of professional specialization include lens design/optical system design, image formation & aberration theory, diffractive optics, and optical and photonic instrumentation. He is a Fellow of the Optical Society of America, and the International Society for Optics and Photonics (SPIE). He is the Editor-in-Chief of the archival journal, Journal of Optics, (Springer) in collaboration with the Optical Society of India.​