Acoustical resonant absorption of pulsed laser radiation by a spherical absorber

作者：Faraggi Eshel^*; Gerstman Bernard S

来源：Journal of Applied Physics, 2007, 102(12): 123505.

DOI：10.1063/1.2822247

We investigate the thermomechanical response of a spherical absorber to pulsed laser radiation and the potential for causing damage to the absorber and the surrounding material due to shockwave and bubble formation. We calculate the expected response of a spherical absorber to a series of laser pulses as a function of the gap duration between the pulses. We model two common absorbers that have different characteristics: a 1 mu m melanosome found in the retina, and a 100 nm gold particle. We find that the thermomechanical response strongly depends on the duration between pulses and displays resonant effects with a characteristic period that depends on the absorber properties. This allows tuning the duration between pulses to channel a greater or lesser fraction of the absorbed energy into shockfront and bubble production, presenting various possibilities such as delivering large amounts of laser energy to produce strong thermal effects while suppressing unwanted pressure effects in the surrounding material. Resonance can also be used to target absorbers of a specific size, allowing generation of shockfronts in localized target regions to destroy specific cells. This specificity can also be used to sort particles by size.

• 出版日期2007-12-15