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Proceedings Paper

Laser-tissue interaction with fs pulses: measurement of the recoil momentum by laser Doppler vibrometry
Author(s): Dirk Mittnacht; Gaetano Sessa; Michele Travaglini; Hans-Jochen Foth
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Paper Abstract

In the field of otolaryngology a precise contactless treatment of the bones in the middle ear is eligible. For this reason lasers are investgiated for the use in this field. The main risk during laser surgery in the middle ear (e.g. stapedotomy) is the damage of hair cells in the inner ear due to heat diffusion or high pressure fluctuations. While the temperature problem has been resolved by shortening the pulse durations; the transfer of a recoil momentum due to the ablation process rises as another problem. To measure this momentum, special spring plates were designed as vibration disks for the mounting of the tissue. The probes were exposed to amplified Ti:Sapphire laser pulses with a pulse length of 45 fs and a power density up to 5,6•1013 W/cm2. The beam of a laser Doppler vibrometer was focused on backside of the plate to monitor its motion. The results were compared to a damage threshold of hair cells in the inner ear calculated by a literature value for the Sound Pressure Level (SPL)-Threshold. The results lead to SPL values below the critical value of 160 dB. Measurements with higher time resolution and high speed photography are used to approve these results.

Paper Details

Date Published: 22 June 2004
PDF: 8 pages
Proc. SPIE 5503, Sixth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, (22 June 2004); doi: 10.1117/12.579542
Show Author Affiliations
Dirk Mittnacht, Univ. Kaiserslautern (Germany)
Gaetano Sessa, Univ. degli Studi di Ancona (Italy)
Michele Travaglini, Univ. degli Studi di Ancona (Italy)
Hans-Jochen Foth, Univ. Kaiserslautern (Germany)

Published in SPIE Proceedings Vol. 5503:
Sixth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications
Enrico Primo Tomasini, Editor(s)

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