Ablative laser — A laser that removes the top layer of skin tissue (ablates it) to trigger resurfacing. Powerful results, longer downtime. The alternative, fractional, splits the beam into tiny columns so healing is faster.Alexandrite laser (755nm) — A wavelength strongly absorbed by melanin: fast and effective on light skin, risky on dark skin. Often combined with 808nm and 1064nm in multi-wavelength machines.Cartridge — The consumable unit of a HIFU machine that contains the focused ultrasound transducers and shot budget. Shot count per cartridge (e.g. 21,000) is the number that decides your long-term running cost.Chloasma — Stubborn patchy pigmentation (melasma), often hormonal. Treated gently with split-pulse modes like PTP on picosecond lasers; aggressive settings risk rebound darkening.CO2 laser (10600nm) — A wavelength absorbed strongly by water, making it the gold standard for resurfacing, scars, and gynecological treatments. Delivered fractionally in modern machines.Contact cooling — A cooling element pressed against the skin during treatment (sapphire tips, TEC). Protects the surface so the laser can work deeper — the difference between comfortable sessions and painful ones.Diode laser (808nm) — A solid-state laser used mainly for hair removal; 808nm sits between Alexandrite and Nd:YAG, making it the all-round wavelength for most skin types.Energy fluence (J/cm²) — The amount of laser energy delivered per square centimeter. Higher fluence does more, but only if the cooling can keep up. A wide adjustable range (e.g. 5–140 J/cm²) means one machine covers delicate and aggressive work.Epidermis / Dermis — The two main skin layers. Superficial treatments work the epidermis; deeper resurfacing and collagen work targets the dermis.Fitzpatrick skin type — The I–VI scale classifying skin tone and reaction to light. Machines and settings are matched to it; a true multi-wavelength system covers I–VI.Fractional — A laser delivery mode that splits the beam into thousands of microscopic columns, leaving skin bridges intact for fast healing. The standard for modern resurfacing.HIFU — High-Intensity Focused Ultrasound: focused ultrasound energy reaching the SMAS layer for non-invasive lifting, without cutting the skin.IPL — Intense Pulsed Light: broad-spectrum flash light, gentler and cheaper than lasers but less precise; used for maintenance and hair reduction at home or salon level.Laser bar — The semiconductor array that produces the laser energy (e.g. USA Coherent bars). Bar quality and shot rating (e.g. 100 million shots) decide how long the machine holds its output.Melanin — The skin pigment that laser wavelengths target. Matching wavelength to melanin depth (and skin type) is the whole game in pigment and hair treatments.Nanosecond vs Picosecond — Pulse duration. Nanosecond (Q-Switch) works mostly by heating; picosecond (10⁻¹² s) works by a mechanical shockwave that shatters pigment into finer particles — fewer sessions, less heat damage.Nd:YAG (1064nm) — A deep-penetrating wavelength, safest for dark skin and coarse hair. The “dark skin” member of multi-wavelength laser sets.Pulse width — How long each laser pulse lasts (e.g. 1–400ms). Shorter pulses with proper cooling are generally safer and more comfortable; longer pulses suit hair removal.Q-Switch — The older nanosecond technology for tattoo and pigment removal. Still effective, but needs more sessions than picosecond for the same result.Selective photothermolysis — The principle behind laser treatment: a wavelength chosen to be absorbed by one target (melanin, ink, water) with pulse length short enough that heat stays in the target. Everything else is engineering around this rule.SMAS — The superficial muscular aponeurotic system, the connective layer a facelift surgeon tightens. HIFU reaches it at 4.5mm depth for a non-surgical lift.Spot size — The area each pulse covers (e.g. 15×26mm, 30×30mm). Larger spots treat faster; smaller spots reach finer detail. Machines with several heads or adjustable spots cover both.TEC cooling — Thermoelectric cooling, a solid-state cooling element often paired with sapphire contact tips. The spec to check when a salesman says “ice cooling” — ask what the actual surface temperature is (e.g. down to -42°C).Wavelength — The color/frequency of the light, measured in nanometers. It decides what the laser targets and how deep it goes. A multi-wavelength machine is a multi-treatment machine.
Why this glossary exists
Because the machines we build sit on the other side of these terms — and we’d rather you compare us on specs you understand than on marketing you don’t. If a term above raises a question about your purchase, ask us directly: we answer the technical questions in writing, before you buy.📧 Email: peterchen@perfect-lasers.com.cn💬 WhatsApp: +86 157 3329 8930 (Click to chat)👉 Started with the glossary? The 2026 Diode Laser Buying Guide with ROI Analysis puts these terms to work.