Spiral-structured crystal of ethylenediamine sulfate fabricated by optical trapping

An Chieh Cheng*, Teruki Sugiyama, Keiji Sasaki

*Corresponding author for this work

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

1 Scopus citations


Optical trapping realizes the formation of a unique spiral-structured crystal of ethylenediamine sulfate (EDS). When a continuous-wave laser beam of 1064 nm is tightly focused at the air/solution interface of EDS aqueous saturated solution, the EDS crystal is induced at the laser focus and is grown by further laser irradiation, and the crystal growth with a spiral structure is observed. Intriguingly, the preliminary experimental data suggest that the growth direction of spiral- structured crystal corresponds to the handedness of circular polarization of the incident light. We propose that the growth direction is determined by the transfer of the angular momentum of incident circularly polarized laser to the growing crystal due to crystal birefringence.

Original languageEnglish
Title of host publicationOptical Manipulation and Structured Materials Conference
EditorsTakashige Omatsu, Kishan Dholakia, Sile N. Chormaic
ISBN (Electronic)9781510663398
StatePublished - 2023
EventOptical Manipulation and Structured Materials Conference 2023 - Yokohama, Japan
Duration: 17 Apr 202321 Apr 2023

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceOptical Manipulation and Structured Materials Conference 2023


  • circular polarization
  • crystal growth
  • ethylenediamine sulfate
  • optical trapping
  • spiral-structured crystal


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