Enhanced eumelanin emission by stepwise three-photon excitation Conference Paper
| Authors: | Kerimo, J.; Rajadhyaksha, M.; DiMarzio, C. A. |
| Title: | Enhanced eumelanin emission by stepwise three-photon excitation |
| Conference Title: | Multiphoton Microscopy in the Biomedical Sciences XI |
| Abstract: | Eumelanin fluorescence from Sepia officinalis and black human hair was activated with near-infrared radiation and multiphoton excitation. A third order multiphoton absorption by a step-wise process appears to be the underlying mechanism. The activation was caused by a photochemical process since it could not be reproduced by simple heating. Both fluorescence and brightfield imaging indicate the near-infrared irradiation caused photodamage to the eumelanin and the activated emission originated from the photodamaged region. At least two different components with about thousand-fold enhanced fluorescence were activated and could be distinguished by their excitation properties. One component was excited with wavelengths in the visible region and exhibited linear absorption dependence. The second component could be excited with near-infrared wavelengths and had a third order dependence on the laser power. The third order dependence is explained by a step-wise excited state absorption (ESA) process since it could be observed equally with the CW and femtosecond lasers. The new method for photoactivating the eumelanin fluorescence was used to map the melanin content in human hair. © 2011 SPIE. |
| Keywords: | melanin; fluorescence; imaging; photons; multiphoton processes; infrared radiation; absorption; infrared devices; near-infrared; nonlinear; stepwise excitation; three photon excitation; three-photon excitation; infrared lasers; laser optics; excited states |
| Journal Title | Proceedings of SPIE |
| Volume: | 7903 |
| Conference Dates: | 2011 Jan 23-25 |
| Conference Location: | San Francisco, CA |
| ISBN: | 0277-786X |
| Publisher: | SPIE |
| Date Published: | 2011-01-01 |
| Start Page: | 79031X |
| Language: | English |
| DOI: | 10.1117/12.873598 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - Progress in Biomedical Optics and Imaging - Proceedings of SPIE - Progr. Biomed. Opt. Imaging Proc. SPIE - "Conference code: 84640" - "Export Date: 23 June 2011" - "Article No.: 79031X" - "Sponsors: The Society of Photo-Optical Instrumentation Engineers (SPIE); Becker and Hickl GmbH; Boston Electronics; Chroma Technology; Coherent, Inc." - 23 January 2011 through 25 January 2011 - "Source: Scopus" |
