With the rapid development of medical cosmetology technology, laser treatment has become the first choice for many beauty lovers. This article will analyze the key laser terms: power, power density, and laser intensity in detail to help you have a more comprehensive understanding of the professional knowledge in the field of medical cosmetology.

Power, power density, laser intensity
Laser power refers to the energy released by the laser per unit time, usually in watts (W). It plays an important role in the application of medical cosmetology, directly affecting the treatment effect, accuracy and safety. High-power lasers can release a large amount of energy in a short period of time and are suitable for treatments that require deep action and a large amount of treatment, while low-power lasers are used for delicate operations and surface treatments.

Two other important concepts derived from laser intensity are laser intensity and power density. These two terms actually represent the same meaning, that is, the energy intensity of the laser beam per unit time and per unit area, which is related to the power and spot diameter of the laser. It is usually measured in watts per square centimeter (W/cm²), which represents the energy transmitted by the laser per unit area and per unit time.

The concepts closely related to laser power, laser power density, and laser intensity include laser energy and energy density. Among them, laser energy refers to the total energy released by the laser during the emission process, usually in joules (J), and energy density refers to the distribution of laser energy per unit area, and the commonly used unit is joules per square centimeter (J/cm²).

The energy of a long-pulse laser refers to the laser energy carried by a single pulse, which determines the ability of the laser to act on the target tissue. In long pulse laser therapy, energy density reflects the energy distribution of the laser on the surface of the skin or other tissues, which usually affects the treatment effect and tissue response. In laser therapy, energy and energy density are two important physical quantities that directly affect the treatment effect and safety. In the field of medical cosmetology, the control of laser energy is particularly critical because it directly affects the accuracy and effect of the treatment.

The formula relationship of the above concepts is as follows:

Specifically:

The total laser energy refers to the total energy delivered by the laser beam during the pulse duration and the total spot area, and the unit is joule (J).

Laser energy density refers to the total energy delivered by the laser beam per unit area during the pulse duration, and its unit is joule/square centimeter (J/cm²).

Laser power refers to the energy delivered by the laser beam per unit time and total spot area, representing the energy transfer rate, and its unit is watt (indicated by capital "W"). 1 watt = 1 joule/1 second.

Laser intensity refers to the energy delivered by the laser beam per unit time and per unit area, representing the energy intensity, which is related to the power and spot diameter of the laser beam, and is usually measured in watts per square centimeter (W/cm²).

Laser power density refers to the energy delivered by the laser beam per unit time and per unit area, and its calculation formula is "power density = energy density ÷ pulse duration". Since the unit obtained by joule/time is watt, the unit of power density is watt/square centimeter (W/cm²). It can be seen that power density is actually another expression of laser intensity.

1.Basic Principles of Laser Power

The laser power determines the intensity of the energy output of the laser to the target tissue during the treatment process. The main functions of laser energy in medical aesthetics include heating, cutting, ablation, etc. Different power settings will affect the effectiveness and safety of these operations.

1. High-power lasers
High-power lasers can quickly release a large amount of energy and are suitable for deep tissue treatment. For example, in laser tattoo removal, high-power lasers can effectively destroy deep ink particles so that they can be metabolized and eliminated by the body. In laser skin tightening treatment, high-power lasers heat collagen deep in the skin, which helps it shrink and regenerate, thereby improving skin elasticity and firmness. This type of treatment requires precise control of power to ensure that enough heat acts on deep tissue without damaging the surface skin.

2. Low-power lasers
Low-power lasers are suitable for surface treatments and delicate operations, such as laser spot removal and laser skin resurfacing. Low-power lasers can precisely act on the surface layer of the skin to help remove spots and other epidermal problems while reducing interference with deeper tissues. For example, when lasers are used to remove spots, low-power lasers can gently act on the pigment layer to avoid damaging the surrounding normal skin.

2. The Importance of Power Regulation in Medical Aesthetics
The regulation of laser power is critical in medical aesthetics because different treatment needs and skin types require different power settings to achieve the best results. The key to regulating laser power is to balance effectiveness and safety, ensuring that the treatment is both effective and does not cause excessive damage to the skin.

1. Laser Spot Removal
During the spot removal process, the power setting determines the extent of laser damage to the pigment. Too high a power may cause skin burns or pigmentation, while too low a power may not effectively remove the spots. Therefore, doctors need to adjust the power according to the depth and type of the spots to achieve the best treatment effect.

2. Laser Skin Resurfacing
Laser skin resurfacing treatment promotes the formation of new skin by removing dead cells and diseased tissue from the surface of the skin. The appropriate power setting can ensure effective removal of surface cells while avoiding damage to the deeper layers of the skin. Too high a power may cause skin burns or a prolonged recovery period, while too low a power may not be effective.

3. Laser Skin Tightening
In laser skin tightening treatment, the power setting directly affects the heating and shrinking effect of collagen. Too high a power may cause discomfort or burns to the surface of the skin, while too low a power may not achieve the desired skin tightening effect. Correct power adjustment helps maintain skin comfort while stimulating collagen regeneration.

· Summary ·
The application of laser power in medical aesthetics needs to be precisely adjusted according to the specific treatment purpose and the patient's skin condition. High-power lasers are suitable for deep treatments and larger treatment volumes, while low-power lasers are suitable for surface treatments and delicate operations. By properly adjusting the laser power, side effects and skin damage can be minimized while ensuring the treatment effect. Doctors need to optimize the power setting according to different treatment needs and skin characteristics to achieve the best cosmetic effect.