How Should Laser Power Change If You Move the Handpiece Away from the Skin?

Short and clear answer:
When you move the handpiece away from the skin, you need to increase the power (fluence in J/cm²) — and quite significantly.Why this happens (physics in two words)
Most modern 808 nm diode lasers are contact systems with a sapphire tip. They are designed to work in full optical and thermal contact (pressed against the skin). When you lift the handpiece even 1–3 mm:

1. An air gap appears → part of the beam is reflected from the skin surface (losses 20–60% depending on angle and distance).
2. The beam diverges → the spot on the skin becomes larger, energy density (J/cm²) drops proportionally to the square of the distance.
3. Cooling worsens — skin receives less pre-cooling from the cold sapphire.
4. Part of the energy scatters in the air → the follicle receives less heat.

Approximate numbers (orientational, 808 nm, 12×12–14×14 mm spot):

• Distance 0 mm (full contact): 0% loss → standard 20–35 J/cm² → normal effect, comfortable.
• 1–2 mm: 20–40% loss → increase fluence by 30–50% (e.g., from 28 → 38–42 J/cm²) → already noticeably weaker, may require adjustment.
• 3–5 mm: 50–80% loss → increase by 80–150% (may reach 50–60 J/cm²) → effectiveness drops sharply, burn risk rises.

5–7 mm: 80–95%+ loss → raising power becomes useless — better not to do it → almost no effect, only skin heating.

Practical rules from cosmetologists (2025–2026):

• Never intentionally lift the handpiece more than 1 mm — this is the most common beginner mistake.
• If you have to slightly lift it (uneven area, client twitched):

• Raise fluence by 30–60% from base value
• Slow down the movement speed (more time per pulse)
• Increase pulse duration (from 30 ms to 60–100 ms)
• Monitor skin reaction 2–3 times more carefully
  • Best practice: always keep full contact, lightly pressing (but without pain).

One-sentence conclusion:
The farther you move the handpiece away, the more you need to raise the power — but it's far more effective and safer to avoid doing this altogether.Keep contact — get maximum results with minimal settings and minimal risks.