Optical and Quantum Electronics

, Volume 34, Issue 12, pp 1251–1266

Wavelength dependent damage in biological multi-photon confocal microscopy: A micro-spectroscopic comparison between femtosecond Ti:sapphire and Cr:forsterite laser sources

  • I.-H. Chen
  • S.-W. Chu
  • C.-K. Sun
  • P.-C. Cheng
  • B.-L. Lin
Article

DOI: 10.1023/A:1021303426482

Cite this article as:
Chen, I., Chu, S., Sun, C. et al. Optical and Quantum Electronics (2002) 34: 1251. doi:10.1023/A:1021303426482

Abstract

Molecular excitation by the simultaneous absorption of two photons provides intrinsic three-dimensional resolution in laser scanning fluorescence microscopy. Thus induced two-photon absorption and the accompanied multi-photon absorption/ionization not only cause photo-bleaching but also cell damage in the vicinity of the focal point. In this paper, we study the wavelength dependent cell damage induced by high intensity femtosecond near infrared lasers. The study was performed with a Ti:sapphire laser and a Cr:forsterite laser. With a longer output wavelength from a Cr:forsterite laser, multi-photon absorption and auto-fluorescence were found to be significantly suppressed and the destructive plasma formation was found to be greatly reduced. Sustained multi-photon spectra can be observed in most plant specimens with a tightly focused Cr:forsterite laser beam under long term irradiation with more than 100 mW laser average power. In contrast, multi-photon absorption induced destructive plasma formation were frequently observed with a tightly focused Ti:sapphire laser beam within seconds with more than 10 mW laser average power.

cell damageCr:forsterite lasermulti-photon absorptionplasma formationTi:sapphire lasertwo-photon fluorescence microscopy

Copyright information

© Kluwer Academic Publishers 2002

Authors and Affiliations

  • I.-H. Chen
    • 1
  • S.-W. Chu
    • 1
  • C.-K. Sun
    • 1
  • P.-C. Cheng
    • 1
  • B.-L. Lin
    • 3
  1. 1.Department of Electrical Engineering and Graduate Institute of Electro-Optical EngineeringNational Taiwan UniversityTaipeiTaiwan, ROC
  2. 2.Department of Electrical EngineeringState University of New YorkBuffaloUSA
  3. 3.Institute of Molecular BiologyAcademia SinicaTaipeiTaiwan, ROC