In the realm of medical aesthetics, the application of laser technology has become increasingly prevalent, with the choice of laser wavelength being crucial for treatment outcomes. Lasers of varying wavelengths possess distinct depths of penetration and target tissue characteristics, which endow them with unique advantages in skin treatment, pigment removal, wrinkle reduction, and more. Understanding the properties of different laser wavelengths is not only instrumental for physicians in selecting the appropriate treatment plans but also helps patients better comprehend the treatment process and expected results. This article delves into the depths achievable by various laser wavelengths and their corresponding target tissues, providing you with a comprehensive understanding of laser treatment knowledge.
Wavelength and Target Tissue:
In the field of medical aesthetics, the application of laser technology relies on a profound understanding of the interaction between different laser wavelengths and target tissues. The depth of the wavelength determines the depth of the skin that the laser can reach, while the absorption characteristics of the target tissue directly affect the treatment outcome. This article will explore the absorption characteristics of the three main target tissues—hemoglobin, melanina, and water—at different wavelengths and how these characteristics guide the selection of clinical treatments.
- Hemoglobin Absorption Spectrum
- Hemoglobin primarily absorbs at peaks of 415nm, 542nm, and 577nm. In the visible light range, light below 600nm is strongly absorbed by hemoglobin, while light above 600nm is less absorbed.
- Melanin Absorption Spectrum
- Melanin absorbs strongest in the ultraviolet region (below 400nm), with absorption gradually weakening as the wavelength increases. There is still significant absorption before 800nm, and absorption decreases after 800nm.
- Water Absorption Spectrum
- Water absorbs less in the visible light region (400–700nm), but absorbs significantly more in the near-infrared region (>900nm), especially at absorption peaks of 970nm, 1200nm, 1450nm, and 1950nm.
- Clinical Significance:
- The 532nm (green light) is strongly absorbed by hemoglobin and melanin, suitable for treating vascular lesions and pigmented lesions.
- The 1064nm (near-infrared light) is less absorbed by hemoglobin and melanin, suitable for deep tissue penetration and reducing the risk of epidermal pigmentation.
- Wavelengths of 1550nm and above primarily act on the water in tissues, effectively used for deep skin heating or fractional laser skin resurfacing.
Wavelengths and Depth:
In the field of medical aesthetics, the application of laser technology is becoming increasingly widespread, and the relationship between laser wavelength and the depth of skin penetration is a key factor affecting treatment outcomes. Different wavelengths of lasers penetrate the skin to varying depths, which directly affects the target tissues and efficacy of laser treatments.
- The Relationship Between Laser Wavelength and Penetration Depth
- Short-wavelength lasers (such as ultraviolet light): Typically have a shallow penetration depth, mainly acting on the epidermal layer. Light with wavelengths below 300nm is strongly absorbed by melanin and proteins in the skin, and the penetration depth usually does not exceed 0.1mm.
- Visible light lasers (such as 532nm, 585nm): These wavelengths of lasers can penetrate the epidermis and the upper dermis, suitable for treating superficial pigmentary and vascular lesions. The penetration depth of 532nm wavelength lasers is generally less than 1mm, mainly used for the treatment of superficial blood vessels.
- Mid-wavelength lasers (such as 1064nm): Nd:YAG laser with a wavelength of 1064nm has strong penetration capabilities, reaching depths of 2-8mm, suitable for treating deep skin issues, such as deep vascular and pigmentary lesions.
- Long-wavelength lasers (such as 1550nm, 2940nm): These wavelengths of lasers primarily act on water and can penetrate deep into the dermis, suitable for skin reconstruction and deep heating. The penetration depth of 1550nm lasers can reach 1.5-3mm, while 2940nm erbium lasers are used for wrinkle reduction and skin reconstruction.
- Clinical Significance of Laser Penetration Depth
- Selection for different lesions: Choosing the appropriate laser wavelength based on the depth and nature of the lesion is crucial. For example, 532nm or 585nm lasers are commonly used for treating superficial freckles and blood vessels; for deep pigmentation or vascular lesions, 1064nm lasers are required.
- Safety and efficacy: Choosing the right wavelength not only improves treatment outcomes but also reduces damage to surrounding normal tissues. Lasers with wavelengths that are too short may cause epidermal damage, while those that are too long may not effectively target the desired tissues.
