Laser diode systems for photodynamic therapy and medical diagnostics

Eva Samsöe Andersen

Research output: ThesisDoctoral Thesis (compilation)

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Abstract

This work concerns techniques for improvement of the coherence properties of diode lasers so that they may be used in two specific medical applications: (Interstitial) photodynamic therapy (PDT) and laser-induced fluorescence diagnostics. In the first application, spatial coherence is crucial, since the treatment light should be delivered through relatively thin optical fibers to optimize treatment and to facilitate minimally invasive treatment. In the second application, a pulsed, blue source at 405nm is desired. This has been approached by frequency doubling the output from an external-cavity laser diode at 810nm. Thus, both spatial and temporal coherence are important to ensure that the second harmonic generation is efficient.

Two red (635nm) laser diode systems for PDT, a first and a second generation, have been developed and tested in preliminary clinical trials. The first generation system is based on asymmetrical optical feedback from a barium titanate crystal. This system is coupled into a thin (50µm core diameter) optical fiber and tested in preliminary experimental trials involving interstitial PDT of solid tumors in rat. The second generation system couples two similar systems by means of polarization coupling, whereby the output power is doubled. The individual systems are based on asymmetrical feedback from ordinary mirrors. This system has been tested in PDT treatment of skin cancer in human and has been compared with a conventional treatment.

For laser-induced fluorescence diagnostics, an 810nm external-cavity laser diode system with improved spatial and temporal coherence has been constructed. The system is based on a new configuration that employs double feedback from the first diffracted and the zeroth reflected order of a diffraction grating. The output from this system is frequency doubled to 405nm using a single pass configuration with a periodically poled KTP crystal. It has been shown that the double grating feedback improves the second harmonic conversion efficiency by several orders of magnitude as compared with the freely running laser.
Original languageEnglish
QualificationDoctor
Awarding Institution
  • Atomic Physics
Supervisors/Advisors
  • [unknown], [unknown], Supervisor, External person
Award date2004 Nov 12
Publisher
ISBN (Print)91-628-6144-1
Publication statusPublished - 2004

Bibliographical note

Defence details

Date: 2004-11-12
Time: 13:15
Place: Dept of Physics, Sölvegatan 14, room B, Lund Institute of Technology.

External reviewer(s)

Name: Krakowski, Michel
Title: Dr
Affiliation: THALES Research and Technology France, Orsay, France

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Paper I:E. Samsøe, P. M. Petersen, P. E. Andersen, S. Andersson-Engels, and K. Svanberg, "A novel diode laser system for photodynamic therapy", In: Laser-tissue interactions, therapeutic applications, andphotodynamic therapy, eds. R. Birngruber, H. van den Bergh, Proc. SPIE 4433, 134-139 (2001).
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Paper II:E. Samsøe, P. Malm, P. E. Andersen, P. M. Petersen, and S.Andersson-Engels, "Improvement of brightness and output power of high-power laser diodes in the visible spectral region", Opt. Commun. 219, pp. 369-375 (2003).
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Paper III:E. Samsøe, P. E. Andersen, S. Andersson-Engels, and P. M. Petersen, "Improvement of spatial and temporal coherence of a broad area laser diode using an external-cavity design with double grating feedback", Opt. Express 12, pp. 609-616 (2004).
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Paper IV:E. Samsøe, P. M. Petersen, S. Andersson-Engels, and P. E. Andersen, "Second harmonic generation of 405 nm using periodically poled KTiOPO4 pumped by external-cavity laser diode with double grating feedback", Submitted to Appl. Phys. B.
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Paper V:E. Samsøe, N. Kjærgaard, H. Lausen, P. E. Andersen, and P. M. Petersen, "An external-cavity laser diode at 635 nm for laser display applications", Submitted to Opt. Commun.
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Paper VI:P. M. Petersen, E. Samsøe, S. Blaabjerg, and P. E. Andersen, "Guiding of laser modes based on four-wave mixing in a semiconductor amplifier", Manuscript in preparation for Phys. Rev. Lett.

Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics

Keywords

  • quasi-phasematching
  • photodynamic therapy
  • laser-induced fluorescence
  • medical laser systems.
  • Histology
  • cytochemistry
  • histochemistry
  • tissue culture
  • Histologi
  • Laserteknik
  • Laser technology
  • cytokemi
  • histokemi
  • vävnadskultur
  • Diagnostik
  • Diagnostics
  • second harmonic generation
  • pulsed lasers
  • spatial filtering
  • Diode lasers
  • optical feedback
  • Fysicumarkivet A:2004:Samsöe Andersen

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