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Optics Letters

Optics Letters


  • Editor: Alan E. Willner
  • Vol. 33, Iss. 12 — Jun. 15, 2008
  • pp: 1345–1347

Autoconfocal microscopy with a cw laser and thermionic detection

Daryl Lim, Kengyeh K. Chu, and Jerome Mertz  »View Author Affiliations

Optics Letters, Vol. 33, Issue 12, pp. 1345-1347 (2008)

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We introduce an application of thermionic emission in a PMT photocathode. Because of the nonlinear dependence of thermionic emission on absorbed laser power, a conventional PMT is found to produce a virtual pinhole effect that rejects unfocused light at least as strongly as a physical pinhole. This virtual pinhole effect is exploited in a scanning transmission confocal microscope equipped with a cw laser source. Because the area of the PMT photocathode is large, signal descanning is not required and thermionic detection acts as a self-aligned pinhole. Our technique of thermionic-detection autoconfocal microscopy is further implemented with graded-field contrast to obtain enhanced phase-gradient sensitivity in unlabeled samples, such as rat hippocampal brain slices.

© 2008 Optical Society of America

OCIS Codes
(180.0180) Microscopy : Microscopy
(180.1790) Microscopy : Confocal microscopy
(180.5810) Microscopy : Scanning microscopy
(190.4870) Nonlinear optics : Photothermal effects

ToC Category:

Original Manuscript: February 27, 2008
Revised Manuscript: May 3, 2008
Manuscript Accepted: May 11, 2008
Published: June 12, 2008

Virtual Issues
Vol. 3, Iss. 7 Virtual Journal for Biomedical Optics

Daryl Lim, Kengyeh K. Chu, and Jerome Mertz, "Autoconfocal microscopy with a cw laser and thermionic detection," Opt. Lett. 33, 1345-1347 (2008)

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