Time-gated iterative phase conjugation for efficient light energy delivery in scattering media

Dong Young Kim, Seungwon Jeong, Mooseok Jang, Ye Ryoung Lee, Wonshik Cho

Research output: Contribution to journalArticlepeer-review

Abstract

Light waves propagating through complex biological tissues are spatially spread by multiple light scattering, and this spread limits the working depth in optical bioimaging, phototherapy, and optogenetics. Here, we propose the iterative phase conjugation of time-gated backscattered waves for enhancing the light energy delivered to a target object embedded in a scattering medium. We demonstrate the enhancement of light energy delivered to a target object hidden behind a 200-μm-thick mouse skull by more than ten times in comparison with the initial random input. The maximum enhancement was reached in only 10 iterations, more than a hundred times smaller than existing methods based on either a time-gated reflection matrix or iterative feedback optimization of the time-gated reflection intensity. Consequently, the proposed method is less sensitive to sample perturbations. Furthermore, the number of images required for optimization remained almost unchanged with an increase in the illumination area, unlike existing methods, where the convergence time scales with the illumination area. The proposed method provides high operation speed over a wide illumination area, which can facilitate the use of wavefront shaping in practical applications.

Original languageEnglish
Pages (from-to)7382-7391
Number of pages10
JournalOptics Express
Volume28
Issue number5
DOIs
Publication statusPublished - 2020 Mar 2

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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