Laser Beam Shaping and Spot Size

Howard M. Shapiro1

1 Howard M. Shapiro, MD., P.C., West Newton, Massachusetts
Publication Name:  Current Protocols in Cytometry
Unit Number:  Unit 1.6
DOI:  10.1002/0471142956.cy0106s01
Online Posting Date:  May, 2001
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Abstract

One or more lasers are the source of illumination in the majority of fluorescence flow cytometers now in use. A typical laser emits a beam on the order of 1 mm in diameter. For efficient utilization this beam must be shaped and focused to a smaller size to illuminate the cell stream passing through the interrogation point. This unit discusses spot size requirements and the methods by which optimal spot size is achieved.

     
 
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Table of Contents

  • Conflicting Requirements: Sensitivity and Precision
  • Effects of Gaussian Laser Beams on Illumination Uniformity
  • Obtaining High Precision from Seemingly Inadequate Spot Sizes Using High Laser Power
  • Effect of Interactions Between Core and Stream Size on Precision
  • Use of Elliptical Focal Spots to Enhance Sample Throughput
  • Prismatic Expansion Versus Crossed Cylindrical Lenses in Formation of Elliptical Spots
  • Beam Shaping for Multiple‐Laser Flow Cytometers
  • Literature Cited
  • Figures
     
 
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Materials

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Figures

Videos

Literature Cited

Literature Cited
   Loken, M.R. and Stall, A.M. 1982. Flow cytometry as an analytical and preparative tool in immunology. J. Immunol. Methods 50:R85‐R112.
   Shapiro, H.M. 1995. Practical Flow Cytometry, 3rd ed. Wiley‐Liss, New York.
   van den Engh, G. and Farmer, C. 1992. Photo‐bleaching and photon saturation in flow cytometry. Cytometry 13:669‐677.
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