Integrated microsphere arrays: Light focusing and propagation effects

Arash Darafsheh, Matthew D. Kerr, Kenneth W. Allen, Nathaniel M. Fried, Andrew N. Antoszyk, Howard S. Ying, Vasily N. Astratov

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

10 Scopus citations


Integration of microspheres inside micro-capillaries or hollow waveguides may allow development of compact focusing tools for a variety of biomedical and photonics applications. However, problems associated with developing focusing microprobes involve the multimodal structure of noncollimated beams delivered by fibers and waveguides. By using numerical ray tracing, it is shown that serial spherical microlenses filter out spatially periodic modes which can be used for obtaining tightly focused beams. Experimental studies are performed for spheres with sizes from 10 to 300 μm with different indices of refraction ranging from 1.47 to 1.9. The chains were assembled inside plastic tubing with bore sizes matching the size of the spheres. By using high index spheres, it is demonstrated that these structures are capable of focusing light in contact with tissue. The beam attenuation properties of such chains are found to be in good agreement with numerical modeling results. Potential applications of integrated microsphere arrays include ultra-precise intraocular and neurosurgical laser procedures, photoporation of cells, and coupling of light into photonic microstructures.

Original languageEnglish
Title of host publicationOptoelectronic Integrated Circuits XII
StatePublished - 2010
EventOptoelectronic Integrated Circuits XII - San Francisco, CA, United States
Duration: Jan 27 2010Jan 28 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceOptoelectronic Integrated Circuits XII
Country/TerritoryUnited States
CitySan Francisco, CA


  • Focusing
  • Laser tissue surgery
  • Microlenses
  • Microoptics
  • Microspheres
  • Optical microprobes


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