Computational modeling of stress transient and bubble evolution in short-pulse laser irradiated melanosome particles

Conference · Tue Mar 04 04:00:00 EST 1997

OSTI ID:491885

Strauss, M; Amendt, P A; London, R A; Maitland, D J; Glinsky, M E; Lin, C P; Kelly, M W

Objective is to study retinal injury by subnanosecond laser pulses absorbed in the retinal pigment epithelium (RPE) cells. The absorption centers in the RPE cell are melanosomes of order 1 {mu}m radius. Each melanosome includes many melanin particles of 10-15 nm radius, which are the local absorbers of the laser light and generate a discrete structure of hot spots. This work use the hydrodynamic code LATIS (LAser-TISsue interaction modeling) and a water equation of state to first simulate the small melanin particle of 15 nm responsible for initiating the hot spot and the pressure field. A average melanosome of 1 {mu}m scale is next simulated. Supersonic shocks and fast vapor bubbles are generated in both cases: the melanin scale and the melanosome scale. The hot spot induces a shock wave pressure than with a uniform deposition of laser energy. It is found that an absorption coefficient of 6000 -8000 cm{sup -1} can explain the enhanced shock wave emitted by the melanosome. An experimental and theoretical effort should be considered to identify the mechanism for generating shock wave enhancement.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 491885
• Report Number(s): UCRL-JC--126835; CONF-970231--39; ON: DE97052684
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
DAMAGE
INJURIES
LASER-RADIATION HEATING
MELANIN
PULSED IRRADIATION
RETINA
SHOCK WAVES