Ink doesn't burn off. Get that straight before you read another spec sheet, because Nd:YAG laser tattoo removal is neither a cutting process nor a bleaching one. The laser cracks pigment apart. Your patient's immune system hauls the pieces away over the following weeks. Every number on the parameter list serves that single handoff.
What follows is a technical explainer for equipment buyers, not medical advice. Operators need training. Patients need screening - and some need a dermatologist, not a laser.
Two wavelengths, and what each one can actually reach
A 1064/532 nm platform is two lasers sharing a cavity. The 532 nm line is the 1064 nm beam run through a KTP crystal that halves the wavelength. Same rod, different job.
1064 nm: the deep, dark workhorse
Penetration depth rises with wavelength. Our engineering training material on light-tissue interaction puts that relationship at the centre, and it's why 1064 nm owns dermal work - it reaches where professional ink lives. Melanin in the epidermis barely absorbs it, so it stays usable on darker skin types that a shorter wavelength would cook.
Our device manuals map it plainly: 1064 nm for blue, black and green-blue. Cannarozzo and colleagues, writing in Life in 2021, ran black and blue tattoos at 1064 nm up to 10 J/cm2 and coloured tattoos at 532 nm. Across the full 52-patient cohort - both arms combined - at least 60% clearance was reported, 51.9% of it in the 80-100% band. Mixed cohort. Not a 1064 nm single-arm figure.
532 nm: shallow marks and red tones
Green light gets absorbed hard and stops early. That's the whole point. Our manuals assign 532 nm to red pigment, both wavelengths to coffee and brown - an absorption curve, not a marketing split. The same 2021 cohort capped coloured work at 5 J/cm2, about half the 1064 nm ceiling.
Now the part nobody raises at a trade show. Green ink absorbs in the red end of the spectrum. It wants a 694 nm ruby or a 755 nm alexandrite, and a dual-line Nd:YAG simply has nothing to offer it. Yellow fails differently. Its peaks sit near 440, 470 and 485 nm - shorter than anything a clinical Q-switched system emits, a point Aljubran and colleagues make in Archives of Toxicology (2025). 532 nm is just the closest line on hand, and in the nanosecond domain it clears yellow badly. The published yellow data comes from a 532 nm picosecond device (Alabdulrazzaq and colleagues, Lasers in Surgery and Medicine, 2015). A 755 nm machine won't rescue yellow either. Say that to a client before you sell a package.
Nanoseconds do the work, not joules
Take a free-running Nd:YAG pulse - say 200 mJ over roughly 400 microseconds. Q-switch it, and the same 200 mJ leaves in about 10 ns. Duration drops by a factor near 40,000. Energy never moved, so peak power climbs by that same factor. Our archive briefs new engineers with exactly this arithmetic. Grasp it and the category makes sense.
Why does that matter? Thermal relaxation time - the interval a target needs to shed roughly 63% of its heat - is the clock you're racing. Beat it, and the pigment particle takes the whole load before heat leaks into the surrounding dermis. Miss it, and you're just heating skin.
The fracture itself is mechanical. A 2023 porcine-model study in Scientific Reports describes rapid thermal expansion of the target, then a release of mechanical acoustic waves; the smaller fragments left behind are what macrophages phagocytose and route out through the lymphatic system. That paper also sets the honest ceiling on nanosecond hardware: at equal irradiance, a 150 ps pulse generates on the order of 100 times the tensile stress of a 15 ns Q-switched pulse. Picosecond fractures harder and costs several times more. Nanosecond still clears ink.
Fluence is the number that burns people
Energy alone tells you nothing. Fluence is energy over spot area, and area scales with the square of diameter. Push 400 mJ through a 2 mm spot: near 13 J/cm2. The same 400 mJ through a 4 mm spot: around 3 J/cm2. One click of the regulator, four-fold swing.
So a protocol a colleague passes you is useless without the spot size. Higher fluence fractures pigment harder - our technical documentation is blunt about that - and it also buys blistering and post-inflammatory hyperpigmentation on the wrong skin type. Test shots first. Three to five, low energy, then wait and read the tissue.
Clearance is immunological, and it sets your calendar
After the shot, some fragments push out through the epidermis. The rest sit there until macrophages - activated through the lymphatic system, as our internal training manual puts it - engulf the debris and carry it off. Weeks, not minutes.
Session spacing isn't a scheduling preference, then. It's a biological constraint. The 2021 Life cohort held 8 weeks minimum between sessions, stretching to 12 after the fourth, and averaged 4.6 sessions across a range of 2 to 9. Adverse events stayed minor, but not hands-off: petechiae in seven patients, managed with occlusive dressing plus topical antibiotics and hydrolytic enzymes and resolved in 10-15 days, and two cases of ghosting.
Tell your front desk. A clinic promising removal in three visits is building its own complaint queue. Our tattoo removal notes go deeper on screening and intervals.
Passive Q-switch vs EO Q-switch: what changes at the handpiece
Most buyers skip this. It decides how your energy dial behaves.
Passive Q-switching uses a tetravalent chromium crystal that modulates the cavity on its own. No external trigger. Turn the energy up and you don't get a bigger pulse - you get more pulses. Single-pulse width and peak power stay put. Our archive is explicit on this, and notes a small residual thermal component at high settings.
Active, electro-optic Q-switching puts a polarizer and crystal shutter in the resonator, driven by voltage. One trigger, one pulse. Pulse width stays locked while energy moves - so the dial really changes peak power in that single shot.
Practically: on a passive unit, more energy buys broader coverage at the same shock strength. On an EO unit, a harder single shock on the same particle. A dense black outline that stalled after four sessions cares about that.
QN-03 or QE-01: reading your own caseload
Both consoles run 1064 and 532 nm in the nanosecond domain. Not interchangeable, though. QN-03 against QE-01, line by line:
| Parameter | QN-03 | QE-01 |
|---|
| Q-switch type | Passive | Electro-optic |
|---|
| Pulse width | 6-8 ns | 6 ns |
|---|
| Max single-pulse energy @1064 nm | 400 mJ | 800 mJ |
|---|
| Max single-pulse energy @532 nm | 200 mJ | 400 mJ |
|---|
| Multi-pulse mode | Double and triple pulse, roughly 800 mJ and 1200 mJ at 1064 nm | None - single-pulse energy scales directly |
|---|
| Spot size | 1, 1.5, 2, 2.5, 3, 3.5, 4 mm (seven fixed steps) | 1-7 mm, continuously adjustable |
|---|
| Repetition rate | 1-5 Hz | 1-10 Hz |
|---|
| Beam delivery | No articulated arm | 7-joint articulated arm |
|---|
| Beam profile | Not stated in the equipment file | Flat-top |
|---|
| Cooling | Water plus air | Water plus air |
|---|
Pick QN-03 when ink is a minority of your book. Sunspots, freckles, brow and eyeline pigment, carbon peel work, the odd amateur black tattoo. Small areas don't need 10 Hz, and no arm means no arm alignment, no arm repair bill.
That list hides the riskiest job on the machine. White, flesh-tone and pink inks - and cosmetic brow, lip and eyeliner pigments - very often carry titanium dioxide or iron oxide. A nanosecond pulse chemically reduces those compounds, and the pigment turns grey or black on the spot. Anderson and colleagues documented it in Archives of Dermatology back in 1993, and darkened pigment clears harder than what you started with. So fire one concealed test point, wait, read it - before any full pass over a light-coloured or cosmetic-pigment area. Tell the patient the darkening can be permanent.
Pick QE-01 when tattoos are the business. Large pieces, dense professional ink, back-to-back sessions where the faster rep rate halves chair time. Continuous spot adjustment matters too - fluence tunes smoothly instead of hopping between fixed steps.
Vascular or hair work? Neither box applies - that's the long-pulse Nd:YAG, the thermal side of the same crystal.
What to check at acceptance
Ask for documentation against IEC 60825-1 - laser product classification, 180 nm to 1 mm, and the reason Class 3B and Class 4 systems carry a remote interlock connector. Then ask for the layer above it: IEC 60601-2-22, the particular standard for surgical, cosmetic, therapeutic and diagnostic laser equipment. Both belong in the supplier's file. And the paperwork has to name the model actually shipping - not a sibling.
Then the unglamorous list. Interlock shorting stub, foot pedal, keyed switch, emergency stop - confirm each one works before the crate leaves. Goggles need optical density covering both 1064 and 532 nm; a single-wavelength pair is worse than useless. Purified-water fill and a scheduled exchange - tap water scales a water-cooled cavity. A spare mains fuse. And the flashlamp - the real wear part. Get shot-count expectations and the replacement price in writing at quotation stage, not after year two.
Frequently asked questions
Does 1064 nm or 532 nm remove black ink?
1064 nm. Black and blue pigment absorb it well, and it reaches dermal ink a shorter wavelength never gets to. 532 nm handles red and superficial tones; coffee and brown take both.
How many sessions should we quote a client?
Several, spaced by months - and be honest: it depends on ink density, depth, colour and the patient's own clearance. The 2021 Life retrospective averaged 4.6 sessions, range 2 to 9, at 8 to 12 week intervals. Traceless removal isn't guaranteed for every tattoo.
Is a nanosecond machine obsolete now that picosecond systems exist?
No. Picosecond pulses generate substantially more tensile stress at the same irradiance, so they fracture pigment harder and can shorten a course. They also cost far more to buy and service. Nanosecond Q-switched Nd:YAG stays the workhorse for pigment and ink, which is why most clinics start there.
Why does the same setting behave differently on two Q-switched machines?
Almost always spot size, sometimes Q-switch type. Fluence is energy over spot area, so the same millijoules through a smaller aperture hit far harder. A passive design adds energy by adding pulses; an EO design adds peak power to one pulse. Identical numbers on the display can mean different things at the skin.
Can these platforms treat pigment as well as tattoos?
Yes, and that's the larger part of the market. Sunspots, freckles, nevus of Ota , cosmetic brow and eyeline pigment all sit inside the same wavelength logic - though cosmetic pigment carries the ink-darkening risk described above, so a concealed test point comes first, every time. Melasma is the exception that demands caution - it recurs, it flares, and aggressive settings make it worse rather than better.
References
- Cannarozzo G, Nistico SP, Zappia E, et al. Q-Switched 1064/532 nm Laser with Nanosecond Pulse in Tattoo Treatment: A Double-Center Retrospective Study. Life (Basel). 2021;11(7):699.
- Baleisis J, Rudys R. Comprehensive examination of tattoo removal using a 150 ps Nd:YAG laser in a porcine model. Scientific Reports. 2023;13:13062.
- Aljubran BA, Ross KE, Alexander U, Lenehan CE. Challenges in laser tattoo removal: the impact of titanium dioxide on photodegradation of yellow inks. Archives of Toxicology. 2025;99(4):1371-1385.
- Alabdulrazzaq H, Brauer JA, Bae YS, Geronemus RG. Clearance of yellow tattoo ink with a novel 532-nm picosecond laser. Lasers in Surgery and Medicine. 2015;47(4):285-288.
- IEC 60825-1 - Safety of laser products - Part 1: Equipment classification and requirements (IEC Webstore)
- IEC 60601-2-22 - Medical electrical equipment - Part 2-22: Particular requirements for basic safety and essential performance of surgical, cosmetic, therapeutic and diagnostic laser equipment (IEC Webstore)
- Anderson RR, Geronemus R, Kilmer SL, Farinelli W, Fitzpatrick RE. Cosmetic tattoo ink darkening. A complication of Q-switched and pulsed-laser treatment. Archives of Dermatology. 1993;129(8):1010-1014.