Thermal and mechanical damage of GaAs in picosecond regime

• Published in: Optics and laser technology 2001-09, Vol.33 (6), p.363-369
• Main Authors: Pratap Singh, Amit, Kapoor, Avinashi, Tripathi, K.N., Rvindra Kumar, G.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Gallium arsenide (GaAs); Laser induced surface damage (LIDT); Mechanical damage; Optics; Physics; Radiation effects on optical elements, devices, and systems; Radiation effects on specific materials; Semiconductors; Structure of solids and liquids; crystallography; Thermal damage
• ISSN: 0030-3992; 1879-2545
• DOI: 10.1016/S0030-3992(01)00038-X

An in-depth study of the single pulse and multiple pulse laser ( 35 ps, 10 Hz and 1064 nm ) damage for threshold fluence and greater fluence of GaAs 〈1 0 0〉 single crystal is presented. Damage which starts at a power 2×10 11 W/ cm 2 in the form of pits occurs due to accumulation of laser induced microscopic defects. Effect of multiple pulse at first makes the pits more prominent in the form of Ga emission. Then the topmost layer is removed. If the number of pulses is further increased new pits are formed in the new surface (beneath the removed surface) and the above process is repeated. The thermal model is sufficient to explain this morphology. However, for larger fluences, a large cracking and fracture and the possibility of both Ga and As emission in different ratios suggest that mechanical damage is a dominant feature for higher fluences which arises due to generation of shock waves and rapid vaporization of material. Damage threshold has been calculated with the help of the thermal model given by Meyer et al. which is in good agreement with our experimental results.