Focusing Light Inside Scattering Media with Optical Phase Conjugation

<p>In scattering media such as biological tissue, the heterogeneous refractive index distribution causes light to scatter, which makes the media look opaque and prevents us from focusing light beyond ~1 mm deep inside the media to achieve optical imaging and manipulation. Hence, the ability to focus light deep inside scattering media is highly desired, and it could revolutionize biophotonics by enabling deep-tissue non-invasive high-resolution optical microscopy, optical tweezing, optogenetics, micro-surgery, and phototherapy.</p><p>To break the optical diffusion limit and focus light deep inside scattering media, optical phase conjugation based wavefront shaping techniques, such as time-reversed ultrasonically encoded (TRUE) optical focusing, are being actively developed. In this dissertation, I will describe our efforts to improve the performance (speed, focusing quality and focusing depth) of optical phase conjugation for future in vivo applications. Remarkably, we have focused light through tissue-mimicking phantoms up to 96 mm thick, and through ex vivo chicken breast tissue up to 25 mm thick.</p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biomedical Engineering

Year dc:date.available

2016

Author dc:creator

• Liu, Yan

Contributors dc:contributor

• Lihong V. Wang
• Samuel Achilefu, Mark Anastasio, Timothy Holy, Jung-Tsung Shen

• Adaptive optics
• Focusing light inside scattering media
• Imaging through turbid media
• Optical phase conjugation
• Time reversal
• Time-reversed ultrasonically encoded (TRUE) optical focusing
• Engineering

Statement dc:rights

• I have not registered my thesis with the U.S. Copyright Office, and do not intend to.

Language dc:language

English (en)

Identifier

https://openscholarship.wustl.edu/eng_etds/208

OAI identifier oai:identifier

oai:openscholarship.wustl.edu:eng_etds-1209