Conical refraction as a tool for polarization metrology

Abstract

A method for polarization metrology based on the conical refraction (CR) phenomenon, occurring in biaxial crystals, is reported. CR transforms an input Gaussian beam into a light ring whose intensity distribution is linked to the incoming polarization. We present the design of a division-of-amplitude complete polarimeter composed of two biaxial crystals, whose measurement principle is based on the CR phenomenon. This design corresponds to a static polarimeter, that is, without mechanical movements or electrical signal addressing. Only one division-of-amplitude device is required, besides the two biaxial crystals, to completely characterize any state of polarization, including partially polarized and unpolarized states. In addition, a mathematical model describing the system is included. Experimental images of the intensity distribution related to different input polarization states are provided. These intensity patterns are compared with simulated values, proving the potential of polarimeters based on biaxial crystals.

Conical refraction: fundamentals and applications

“…CR has been also considered for technological applications, being at the heart of a single shot novel polarimeter [131,271] and of a solid state laser [138]. In particular, in Chapter 10 of this thesis we have also reported a free space optical communication (FSOC) system for multiplexing and demultiplexing multiple polarization channels with a cascade of 3 biaxial crystals, see Ref.…”

“…Additionally, due to that for a uniformly polarized input beam there exists a direct link between the intensity distribution of the CR rings and the state of polarization of the input beam, we have demonstrated and patented a single-shot polarimeter based on CR in collaboration with the group of Prof. Juan Campos at the Universitat Autònoma de Barcelona, see Refs. [131,271,272] for further information.…”

“…In CR, for ρ 0 ≫ 1, the SOP of the beam at the focal plane is already well known [54,59,74,131]. In this Chapter we investigate the CR SOP out of the focal plane, including values of ρ 0 1, when Poggendorff fine splitting vanishes.…”

Interferometric characterization of the structured polarized light beam produced by the conical refraction phenomenon

“…This is the case of the unusual beams produced by conical refraction (CR) in a biaxial crystal (BC) [17][18][19], already applied in free-space optical communications [20], in polarization metrology [21] or in particle trapping [22,23]. CR is a fundamental phenomenon in optics with two basic manifestations, internal and external CR, as presented in the classical textbook by Born and Wolf [24].…”

Design of polarimeters based on liquid crystals and biaxial crystals for polarization metrology

“…When light emerges from the biaxial crystal under CR conditions, a ring of light appears whose intensity distribution depends on the incident polarization. The proof of concept of polarization metrology using the conical refraction phenomenon was given in [9], whereas a deep study of the polarimeter performance was provided in [10].…”