LIOB BASED HAIR CUTTING DEVICE

摘要

A laser-based hair cutting device (10) is provided, which device (10) comprises a laser source (18), an optically transparent exit window (15) and optical elements (11, 12, 13, 14) The laser source (18) provides an incident light beam (21) for cutting a hair (22) above and near a skin surface by laser-induced optical breakdown (LIOB) of the hair (22) in a focal position of the light beam (21). The optically transparent exit window has an external exit surface (15) for allowing the incident light beam (21) to leave the device. The optical elements (11, 12, 13, 14) focus the incident light beam (21) in the focal position at a working distance from the exit surface (15). The laser source (18) and the optical elements are arranged and configured such that the working distance is at least (I) wherein NA is a numerical aperture of the incident light beam leaving the device (10), Ep is a pulse energy (J) of the incident light beam (21), Fthresh is a fluence threshold (J/m2) of the exit surface, M2 is a beam quality of the incident light beam (21) and lambda is a wavelength (m) of the incident light beam (21).