Femtosecond Laser Densification of Hydrogels to Generate Customized Volume Diffractive Gratings

Zheng Xiong, Arun Poudel, Ameya R. Narkar, Zhe Zhang, Puskal Kunwar, James H. Henderson, Pranav Soman

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Inspired by nature's ability to shape soft biological materials to exhibit a range of optical functionalities, we report femtosecond (fs) laser-induced densification as a new method to generate volume or subsurface diffractive gratings within ordinary hydrogel materials. We characterize the processing range in terms of fs laser power, speed, and penetration depths for achieving densification within poly(ethylene glycol) diacrylate (PEGDA) hydrogel and characterize the associated change in local refractive index (RI). The RI change facilitates the fabrication of custom volume gratings (parallel line, grid, square, and ring gratings) within PEGDA. To demonstrate this method's broad applicability, fs laser densification was used to generate line gratings within the phenylboronic acid (PBA) hydrogel, which is known to be responsive to changes in pH. In the future, this technique can be used to convert ordinary hydrogels into multicomponent biophotonic systems.

Original languageEnglish (US)
Pages (from-to)29377-29385
Number of pages9
JournalACS Applied Materials and Interfaces
Issue number25
StatePublished - Jun 29 2022


  • densification
  • diffractive grating
  • femtosecond laser
  • hydrogel
  • pH sensor
  • refractive index

ASJC Scopus subject areas

  • General Materials Science


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