Abstract
Pre-shaping light to achieve desired amplitude distributions at the tip of a multimode fiber (MMF) has emerged as a powerful method allowing a wide range of imaging techniques to be implemented at the distal facet. Such techniques rely on measuring the transmission matrix of the optically turbid waveguide which scrambles the coherent input light into an effectively random speckle pattern. Typically, this is done by measuring the interferogram between the output speckle and a reference beam. In recent years, an optical setup where the reference beam passes through the MMF has become an attractive configuration because of the high interferometric stability of the common optical path. However, the merits and drawbacks of an internal reference beam remain controversial. The measurement of the transmission matrix is known to depend on the choice of internal reference and has been reported to result in “blind spots” due to phase singularities of the reference beam. Here, we describe how the focussing efficiency of the calibration can be increased by several percent by optimising the choice of internal reference beam.
Funder
HORIZON EUROPE Framework Programme
Foundation for the National Institutes of Health
Publisher
Public Library of Science (PLoS)
Reference33 articles.
1. Hologram transmission through multi-mode optical fibers;R. Di Leonardo;Opt. Express,2011
2. Shaping the light transmission through a multimode optical fibre: complex transformation analysis and applications in biophotonics;T. Čižmár;Opt. Express,2011
3. Focusing and scanning light through a multimode optical fiber using digital phase conjugation;I. N. Papadopoulos;Opt. Express,2012
4. Compressively sampling the optical transmission matrix of a multimode fibre;S. H. Li;Light. Appl,2021
5. Characterizing Optical Fiber Transmission Matrices Using Metasurface Reflector Stacks for Lensless Imaging without Distal Access;G. S. D. Gordon;Phys. Rev. X 9,2019