Currently available laser delivery techniques used for dermatology, such as for tattoo removal and medical laser ablation, typically operate in the UV, visible, or infrared spectra. Furthermore, current dermatological applications typically involve the propagation of waves using picosecond, nanosecond, microsecond, or millisecond pulse widths, and also involve continuous wave lasers. Often, a fiber optic bundle, articulated mirror system, or the like directs the laser light from a beam source into a hand-piece control unit positioned above the skin and aimed toward the target. This creates an area of free space (i.e., an air gap) between the hand-piece and the target. Because these procedures propagate a laser through free space to illuminate target tissue, they allow for a dangerous degree of electromagnetic energy to be released, both when the wave propagates in free space and when the propagated light reflects off of the target tissue. Under typical circumstances, even a diffuse reflectance of 1% of the transmitted wave into the eyes of an operator or patient is enough to cause permanent ocular damage.
In addition, conventional laser systems exhibit poor heat dissipation at the tissue-air interface. This can exacerbate the negative thermal effects at the tissue surface, which result in potentially drastic changes to the tissue being treated, diminishing overall effectiveness of the treatment, prolonging the time needed to recover between treatments, increasing the number of treatments required, etc. For example, excessive heat can damage or permanently scar the topmost layers of skin, reduce the efficacy of subsequent treatments, and even vaporize water within the tissue. In addition to damaging the target tissue, vaporizing water within the tissue increases the relative fat density at the surface, which causes even more back-scattered light to reflect from the tissue surface during treatment.