Abstract: Methods of applying laser light to the skin, and apparatus therefor, include methods for removing hair, for bleaching hair, for transdermal drug delivery, for sensing a body function, for skin tightening, and for imaging subsurface structures are described. The hair removal methods and the hair bleaching methods include infiltrating a transparent fluid with an index of refraction greater than that of skin tissue into hair ducts to help transmit the laser light down the hair ducts. The transdermal drug delivery and body function sensing methods include exfoliating layers of the stratum corneum from a section of skin with laser light. A transdermal drug delivery patch can be placed over the exfoliated skin section, or an electrical sensor can be placed over the exfoliated skin section.

Abstract: Methods of applying laser light to the skin, and apparatus therefor, include methods for removing hair, for synchronizing hair growth, for stimulating hair growth, for treating Herpes virus, for reducing sweat and body odor, for in situ formation of a chromophore in hair ducts, for reducing light loss at the skin surface, for grafting of hair stem cells, and for removing keloid or hypertrophic scars. The hair removal methods include controlling the proportions of photomechanical and photothermal damage by selection of laser parameters, chromophore particle size and/or pulse duration, with optional dynamic skin cooling. Additional hair removal methods include infiltrating a photoactivated drug into hair ducts and exposing the skin to sunlight or administering an anti-proliferative agent into hair ducts, for example, by encapsulating the anti-proliferative agent in a slow release vehicle.

Abstract: A process for the long term or permanent prevention of growth of unwanted hair. The upper portions of hair ducts (i.e. portions near the skin surface) in a section of skin are infiltrated with a contaminant having a high absorption at at least one frequency band of light. The skin is then illuminated using a process having at least two distinct phases. In a "mechanical" phase the skin section is illuminated (e.g., by a laser) with at least one short pulse of light sufficient to cause tiny explosions in the contaminant forcing portions of the contaminant more deeply into the hair ducts. During a "thermal" phase the skin section is then illuminated so as to heat the contaminant substantially without further explosion or vaporization of the contaminant. The hot contaminant heats portions of the skin tissue immediately surrounding the contaminant to a temperature high enough and for a long enough period of time to devitalize the tissue.