But if so much energy is being delivered so quickly why does that not make the surrounding tissue hot?
The Quantum 2 is equipped with a powerful refrigeration system and cooled sapphire window through which the beam passes. The sapphire window is kept at a temperature just above freezing to prevent ice formation. The melanosomes, melanocytes and nerve sensors are all very small objects, in effect floating in a 70% water bath that is just 0.14mm thick called the epidermis. This is easily cooled by the Quantum 2 cooling tip as the laser is fired and the small objects rapidly lose their heat into the water bath.
In contrast the hair follicle is typically 30,000 times larger than the small objects and cannot dissipate the energy as quickly. It therefore get hot to the point where the follicle tissue is denatured and dies.
In older generation diode lasers it is the heat trapped by the hair follicle and then conducted into the surrounding skin that added to the incident heat and resulted in pain. That element is virtually eliminated in the Quantum method which uses about 50% less energy to give pain free, predictable results.