Controlling the optical wavefronts for multiparametric sensing: Holography cum metamaterial centric perspectives

Optical sensors play an important role in advancing science and technology for improving the standard of living. These sensors work by accessing the alteration in one or more parameters of the optical beam such as phase, intensity, polarization, wavelength, wavefront, etc. through interaction with the test sample. The precise control of an optical wavefront has become important to achieve key functionalities of the optical sensors. Holography is one of the important and easy approaches to controlling and studying the wavefronts. Using this strategy, the wavefront can be examined both through the photographic recording-based conventional holography and through digital holography. Holography-based techniques are being used widely for sensing and imaging applications. Conventional holography-based sensors work by detecting either a change in the diffraction efficiency of the hologram or the wavelength of the beam. Further, digital holography-based sensors detect changes in the phase of the beam. In recent times, metamaterials are emerging as novel materials for many applications including sensing. Metamaterials are artificial subwavelength inclusions structured ingeniously as a potential substitute for materials available in nature. They stimulate an additional degree of freedom by breaking fetters laid by traditional designs to conduct multivariate analysis. This is an infant discipline that can envision the interleaving of multiple devices on a single chip and guide sensing developments of interdisciplinary pursuits. The present work encompasses a comprehensive outlook on optical sensors based on wavefront modulation using holographic and metamaterial-based approaches.