Alexandrite Laser Technology
Alexandrite lasers emit light at 755 nanometers, representing the longest wavelength among the common hair removal lasers. This wavelength provides optimal balance between selective absorption of melanin and penetration depth for hair follicles. The alexandrite laser's efficiency and versatility have made it one of the most widely used lasers in dermatology for hair removal and pigmented lesion treatment.
The 755-nanometer wavelength was specifically chosen for hair removal applications due to its ideal selective photothermolysis characteristics. Alexandrite lasers can be used in long-pulsed mode for hair removal or shorter-pulsed mode for pigmented lesion treatment, adding versatility to a single platform.
Selective Photothermolysis for Hair Removal
Alexandrite lasers target melanin in the hair follicle matrix and bulb. The 755-nanometer wavelength is well absorbed by melanin while providing sufficient penetration to reach deep follicular structures. Long pulse widths (20-40 milliseconds) ensure adequate heating of hair follicles while minimizing epidermal thermal injury.
Key advantages of alexandrite technology include:
- Excellent melanin absorption for effective hair removal
- Appropriate penetration for deep follicular structures
- Rapid repetition rates allow efficient treatment
- Suitable for various skin types with proper settings
- Versatile platform for pigmented lesion removal
Hair Removal Applications
Alexandrite lasers effectively treat unwanted hair on face, body, legs, and sensitive areas. The laser selectively targets dark hair while sparing fair skin. Multiple treatments are required to address all hair in growth phase, typically requiring 6-10 sessions at 6-8 week intervals. Results are progressive, with hair becoming finer and lighter with each treatment.
Alexandrite lasers work most effectively on darker hair and lighter skin types (Fitzpatrick I-III). Results are less dramatic on very light or very coarse hair. Darker skin types require appropriate fluence settings to minimize post-inflammatory hyperpigmentation.
Pigmented Lesion Treatment
Alexandrite lasers can be used in Q-switched mode (nanosecond pulses) for pigmented lesion removal. This application effectively treats solar lentigines, café-au-lait spots, and other benign pigmented lesions. The 755-nanometer wavelength is selectively absorbed by melanin in lesions, causing disruption and clearance.
Treatment Procedure and Parameters
Hair removal treatments require appropriate fluence selection based on skin type and hair characteristics. Cooling during treatment provides comfort and prevents epidermal thermal injury. Treatment sessions typically last 20-60 minutes depending on treatment area size. The rapid repetition rate of alexandrite systems allows efficient coverage of large areas.
Results and Multiple Treatment Requirements
Hair reduction is progressive, with most patients achieving 70-90% permanent hair reduction after completing treatment series. Maintenance treatments at annual or longer intervals may be required to address fine regrowth. Some patients experience permanent hair loss while others require periodic touch-up treatments.
Post-treatment care includes sun protection and avoidance of irritating products. Most patients can resume regular activities immediately post-treatment. Rare complications include hyperpigmentation or hypopigmentation, particularly in darker skin types.