The invention provides a non-invasive 
skin treatment device (200) for generating a multiphoton 
ionization process at a target position (110) in 
skin tissue (102). The 
skin treatment device (200) comprises a 
laser source (105) configured and constructed for generating a 
laser beam (106), an optical 
system (109, 112) for focusing the 
laser beam into the target position below a 
skin surface (103), and a 
plasma unit (117) configured and constructed for generating a 
plasma (100) such that, in use, at least a portion of the 
plasma penetrates the 
skin tissue for generating at least one free 
electron at the target position. The skin treatment device further comprises a 
control unit (123) configured and constructed for controlling the 
laser source and the plasma unit such that, in use, at least a portion of the light of the laser beam is absorbed by said at least one free 
electron generated at the target position, thereby generating the multiphoton 
ionization process. A result of the use of the plasma in generating the multiphoton 
ionization process is that an overall laser beam intensity, required to generate the multiphoton ionization process, is reduced as compared to skin treatment devices which generate the multiphoton ionization process using a laser beam only.