Multiple optical tweezers for micro Raman spectroscopy

Dan Cojoc*, Enrico Ferrari, Valeria Garbin, Enzo Di Fabrizio

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

6 Scopus citations


The goal of our study is to develop a setup that combines multi-trapping and manipulation with micro Raman spectroscopy of microns size particles. Multiple trapping, in 2D or 3D (two or three dimensional) configurations, is obtained in an inverted microscope scheme by shaping the trapping beam (1064 nm) with diffractive optical elements implemented on a spatial light modulator (SLM). Manipulation of multiple particles, directly trapped by the beam, can be achieved using the dynamic displaying of the SLM. Indirect trapping and manipulation of the sample can be obtained surrounding it with trapped micro beads that are manipulated by the optical tweezers. Laser light is not directly focused on the sample but is distributed on the beads and therefore the photo-induced damaging of biological samples is reduced. This technique offers also other advantages: the sample can be kept in a stable position during the spectroscopic investigation or can be moved in x-y-z to get spatial resolved information in a scanning mode measurement and the shape of a deformable sample can be changed in a controlled manner during the measurement. Sample's excitation and Raman signal collection are accomplished with a separate laser beam (514.5 nm) in a non-inverted microscope coupled with the spectrometer. Some experimental results showing multi trapping and indirect manipulation of human red blood cells are presented and discussed.

Original languageEnglish (US)
Article number59300B
Pages (from-to)1-11
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2005
Externally publishedYes
EventOptical Trapping and Optical Micromanipulation II - San Diego, CA, United States
Duration: Jul 31 2005Aug 4 2005


  • Diffractive optical elements
  • Micro Raman spectroscopy
  • Optical tweezers

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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