We report on cell damage of single cells confined in continuous-wave (cw), near-infrared (NIR) multimode optical traps as a result of multiphoton absorption phenomena. Trapping beams at NIR wavelengths less than 800 nm are capable of damaging cells through a two-photon absorption process. Cell damage is more pronounced in multimode cw traps compared with single-frequency true cw NIR traps because of transient power enhancement by longitudinal mode beating. Partial mode locking in tunable cw Ti:sapphire lasers used as trapping beam sources can produce unstable subnanosecond pulses at certain wavelengths that amplify multiphoton absorption effects significantly. We recommend the use of single-frequency long-wavelength NIR trapping beams for optical micromanipulation of vital cells.
© 1996 Optical Society of AmericaFull Article | PDF Article
Y. Liu, M. W. Berns, K. Konig, G. J. Sonek, and B. J. Tromberg
Opt. Lett. 20(21) 2246-2248 (1995)
K. König, P. T. C. So, W. W. Mantulin, and E. Gratton
Opt. Lett. 22(2) 135-136 (1997)
K. König, T. W. Becker, P. Fischer, I. Riemann, and K.-J. Halbhuber
Opt. Lett. 24(2) 113-115 (1999)