Laser plasma interactions in fused silica cavities
- LBNL Library
The effect of laser energy on formation of a plasma inside a cavity was investigated. The temperature and electron number density of laser-induced plasmas in a fused silica cavity were determined using spectroscopic methods, and compared with laser ablation on a flat surface. Plasma temperature and electron number density during laser ablation in a cavity with aspect ratio of 4 increased faster with irradiance after the laser irradiance reached a threshold of 5 GW/cm{sup 2}. The threshold irradiance of particulate ejection was lower for laser ablation in a cavity compared with on a flat surface; the greater the cavity aspect ratio, the lower the threshold irradiance. The ionization of silicon becomes saturated and the crater depths were increased approximately by an order of magnitude after the irradiance reached the threshold. Phase explosion was discussed to explain the large change of both plasma characteristics and mass removal when irradiance increased beyond a threshold value. Self-focusing of the laser beam was discussed to be responsible for the decrease of the threshold in cavities.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Basic Energy Sciences. Chemical Sciences Division
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 842898
- Report Number(s):
- LBNL--54085
- Country of Publication:
- United States
- Language:
- English
Similar Records
Dynamics of femtosecond laser absorption of fused silica in the ablation regime
Plasma formation and structural modification below the visible ablation threshold in fused silica upon femtosecond laser irradiation