Optothermal response and Tissue Damage analysis during Laser Hair Removal

Abstract

Effective design of laser sources is crucial to optimum performance during Laser hair removal. Therefore, the thermal effect of laser sources was evaluated at wavelengths 694, 755, and 1064 nm at different fluence 4.5, 5.5, 10, and 15 J/cm2, respectively. The patient skin models are 3 photo types of a 3-layer 3D model of epidermis, dermis and hypodermis containing the hair shaft and follicle with thickness carefully selected to be in range of a normal human feature. Monte Carlo method, Bio heat transfer and thermal damage analysis using Arrhenius formula were employed. Results show that a laser source of 10-15 J/cm2, at 755 nm wavelength is optimal for light skinned and moderate skinned while 4.5-10 J/cm2, 755-1064 nm is optimal for dark skinned people for a pulse width of 0.1 sec. This work would assist researchers and manufacturers in the design and development of hair photoepilation devices.