摘要

Objectives: The technique of LHR has evolved drastically over the recent past. From the single wave lengths produced by media like Nd:YAG crystal to single wave length diodes to multiple wavelength diodes the world of LHR has seen a sea change. Introduction: LHR was the most sought after laser technique in the initial days since it enjoyed the maximum awareness both amongst the patients and the doctors. At that time lasers were almost synonymous with LHR as most of the people knew only about the hair removal systems. The LHR technique has come a long way from the initial days of a single wavelength to the present day of in motion and multiple wavelength techniques Materials / method: Broadly speaking the shorter wavelengths like 694 nm ruby are better absorbed by melanin than the longer ones like 1064nm and therefore give better results in hair reduction. However the shorter wavelengths are not safe for the skins of color and can be associated with more side effects. The 810nm diode laser is a perfect balance of efficacy and safety in this situation Results: A semiconductor laser converts electric energy into light energy. This happens because of the partial conduction properties of the semiconductor material. By putting specific amounts of impurities into the semiconductor material(doping) the number of negative and positive electrons can be changed. This can help us produce different wavelengths from the same semiconductor Conclusion: The technique of LHR has evolved extensively over the recent past. From single wavelengths to in motion technique to multiple wavelengths shot at the same time using the semiconductor diode lasers. The semiconductor diodes have been the main force behind this evolution The advantages of diode lasers are -Large spot sizes -In motion technology -Solid state lasers -Ability to produce multiple wavelengths