Two quotations land on your desk. One console says 6 ns. The other says 450 ps, costs roughly three times more, and the rep calls it a different generation of technology.
Is it? Sometimes. The honest answer lives in the numbers rather than the category label, and the category label is where most of the noise in this market comes from. What follows is written for people specifying equipment. It isn't medical advice, and nothing here replaces operator training.
Short answer: a well-built Q-switched Nd:YAG runs 5-10 ns, and the picosecond systems clinics actually buy run in the hundreds of picoseconds - roughly a ten to fifteen fold gap, not the thousand-fold one the name implies. The shorter pulse earns its premium on dense professional and multicolour ink. For epidermal pigment work, nanosecond stays the working tool.
Both category names are wider than buyers assume
Start here. It breaks the framing that most brochures depend on.
A well-built Q-switched Nd:YAG pigment platform sits somewhere around 5 to 10 ns. Our two consoles land at 6-8 ns and 6 ns respectively. But "Q-switched" also covers much slower hardware. In Taro Kono's 2020 prospective comparison in Laser Therapy, the nanosecond arm ran at 50 ns. That's roughly eight times wider than a 6 ns pulse, wearing the same two words on the label.
The picosecond side has the mirror-image problem. Joshua Freedman's review of short-pulsed systems in Seminars in Cutaneous Medicine and Surgery tracks the category from its first commercial cutaneous unit onward, and the devices that reached clinics were never the ultrafast research lasers. Kono's picosecond arm measured 375 ps at one wavelength and 450 ps at the other. Compare that with the 35 ps pulses Victor Ross and colleagues used in their 1998 split-tattoo study in Archives of Dermatology. Ten times apart. Both called picosecond.
That's where the ten to fifteen fold figure comes from. Meaningful. Not the thousand-fold leap the word implies.
One machine has several pulse widths
Ask which one you're being quoted. The 532 nm line comes out of a frequency-doubling crystal and often carries a different duration than the 1064 nm fundamental - Kono's 375/450 ps split is exactly that. Multi-pulse or bundle modes change the picture again, because a burst of sub-pulses isn't one short pulse, whatever the total energy reads. A single number on a datasheet, with no wavelength and no mode attached, is not a specification. It's a slogan.
| Pulse width | Marketed as | Where the figure comes from | What it means in practice |
|---|
| 35 ps | Picosecond | Device used in the Ross 1998 split-tattoo study | Research-grade. Shorter than anything sold to clinics today |
|---|
| 375 ps @532 nm / 450 ps @1064 nm | Picosecond | Commercial system in the Kono 2020 comparison | What the word usually means on a quotation you receive |
|---|
| 6 ns | Q-switched, nanosecond | Pmise QE-01, electro-optic | Duration stays locked while you move energy |
|---|
| 6-8 ns | Q-switched, nanosecond | Pmise QN-03, passive | Standard nanosecond pigment and ink work |
|---|
| 50 ns | Q-switched, nanosecond | Nanosecond arm in the Kono 2020 comparison | Same two words on the label, roughly eight times wider than 6 ns |
|---|
What a shorter pulse actually buys
Our engineering training material describes the nanosecond regime plainly: very high power delivered over a very short time, the target absorbing it, then rapid vaporisation and fragmentation - an explosion-like event, with a measure of thermal necrosis alongside. That last clause is the point. Nanosecond work is photomechanical action driven by a photothermal input. Heat is still in the room.
Shorten the pulse and the balance tips. Less time for heat to conduct away from the particle means more of the absorbed energy stays as mechanical stress inside it. The constraint has a name - the pulse needs to be shorter than the time the particle takes to relax that stress - and for small carbon-based ink particles, that window sits below a nanosecond. Which is precisely why the category exists.
The peak-power arithmetic behind all of this, plus the fluence-versus-spot-size trap that catches new operators, is worked through in our Nd:YAG tattoo removal explainer. No point repeating it here.
Where the advantage is documented
Ross's 1998 study put 35 ps against 10 ns on the same black tattoos, 16 patients, 0.65 J/cm2 at the skin surface. Twelve of 16 showed significant lightening on the picosecond side. Nearly two decades later, Lorgeou and colleagues randomised halves of tattoos in 49 patients for JEADV (2018): 33% of picosecond-treated tattoos reached at least 75% reduction in colour intensity versus 14% for the nanosecond laser, p = 0.008. For monochrome black and blue pieces the gap was 34% against 9%.
Kono's 2020 work adds colour detail across 11 patients and 37 professional tattoos. The 1064 nm picosecond line beat the others on black. The 532 nm picosecond line beat the others on red, and on green it beat both the 532 nm nanosecond laser and the 1064 nm picosecond line.
Read those together and a pattern falls out. Dense professional ink, and the colours a nanosecond system handles poorly, are where the shorter pulse earns its price.
Where it doesn't help
Polychromatic tattoos stayed hard for everyone in the Lorgeou cohort - only one of five reached better than 75% improvement, with either technology. Kono's side-effect data is worth reading twice, too: post-inflammatory hyperpigmentation appeared across all four treatment arms, and paradoxical darkening turned up at 5.4%, equally with each laser type. A picosecond pulse does not immunise you against ink darkening on cosmetic or light-coloured pigment. Concealed test point first, same as always.
Then there's the part nobody puts in a comparison table. Faster pulses come from more complex resonators, and complex resonators cost more to buy, more to service, and more to keep aligned. If ink is a small slice of your book, that spend has to earn back from somewhere.
We don't build a picosecond system. Saying so plainly
Our catalogue is nanosecond. The passive QN-03 and the electro-optic QE-01 are Q-switched Nd:YAG platforms, 1064 and 532 nm, in the single-digit nanosecond range. There is no picosecond unit in the line, no picosecond upgrade path, and no pico mode hiding behind a menu. If a shorter pulse is what your caseload demands, buy it from someone who makes one.
Between those two, the split is straightforward. The passive QN-03 fixes peak power per pulse and adds energy by stacking sub-pulses - 400 mJ single, roughly 800 and 1200 mJ in double and triple mode at 1064 nm - through stepped 1-4 mm spots, no articulated arm, 1-5 Hz. Lower capital cost, less to align. The electro-optic QE-01 holds pulse width at 6 ns while single-pulse energy scales to 800 mJ, delivered through a continuously adjustable 1-7 mm spot on a 7-joint arm at 1-10 Hz. A heavy ink caseload and per-case parameter logging point to the QE-01. A mixed pigment book on a tighter budget points to the QN-03.
Nanosecond is enough more often than the trade-show floor suggests. Solar lentigines, freckles, surface pigment, carbon peel work, brow and eyeliner pigment, amateur black tattoos, dermal work such as nevus of Ota over a longer course - all of that sits inside what a Q-switched Nd:YAG does daily. Kono's own study still cleared professional tattoos on the nanosecond arm. Slower, not never.
Go picosecond when dense multicolour professional tattoo removal is the core of the business, when you're competing in a city where clients shop on session count, or when a nanosecond course has already stalled on a specific piece. Those are real reasons. "The competitor down the road has one" is not, unless their appointment book says otherwise.
How to test a pulse width claim before money moves
Four questions, in order. They take a supplier about a day to answer honestly and forever to answer dishonestly.
Ask for a trace, not a number
Pulse width is measured, not declared. A fast photodiode plus an oscilloscope with enough bandwidth produces a waveform, and the specification should say which convention was used - full width at half maximum is the usual one - along with the energy setting the measurement was taken at. A supplier who can show you that plot for the exact model has done the work. A supplier who emails you a brochure page instead has told you something as well.
Do the peak-power arithmetic yourself
Peak power is roughly energy divided by pulse width. Ten seconds of mental arithmetic, and it settles arguments. Run 400 mJ through a 6 ns pulse and you land near 67 MW, which is what our own nanosecond hardware does. Now, one thing to get straight first: GW-class peak power is normal for a picosecond platform. 800 mJ in 450 ps really is 1.8 GW, and commercial 1064 nm pico systems are quoted in that range. Magnitude alone is not the red flag.
The red flag is a page that prints all three numbers and they contradict each other - say 800 mJ, 450 ps, and a peak power line reading 300 MW. Those can't coexist. 800 mJ over 450 ps is 1.8 GW, six times the stated figure, so one of the three is wrong and you need to know which before you sign. Same test in reverse: work the claimed pulse width and peak power back into a single-pulse energy, and see whether the power supply and the rod in that cabinet could plausibly deliver it.
Check that the paperwork names the model
Safety and performance documentation - IEC 60825-1 for laser product classification, IEC 60601-2-22 for the medical laser particulars - should name the model you're actually buying, not a sibling with a similar code. Compare the parameters printed in the certificate against the brochure. They diverge more often than you'd like. For US-cleared devices, the FDA's public 510(k) database is searchable by device and applicant, and the summary documents often state the technological characteristics the clearance rests on. Free, and it takes minutes. Our service and commissioning notes cover the rest of the acceptance checklist.
Watch for the soft words
Pico-effect. Picosecond technology. Pico toning mode. None of those are pulse durations. A model name carrying the pico prefix while the specification table quietly reads in nanoseconds is the oldest trick in this category, and our own archive shows how far back it goes: an older product-history note in our files already treats a verified sub-8 ns single pulse as a differentiator worth printing, back when stated pulse widths in the pigment-laser market weren't to be trusted. That hasn't changed. Only the prefix has.
The short version
Shorter pulses fracture pigment more efficiently, and the published comparisons back that for dense black, blue, red and green ink. The premium is real too, in purchase price and in service. Between those two facts sits a marketing layer that uses the word picosecond far more loosely than the physics does, so make the supplier convert the adjective into a measured number at a stated wavelength.
Then decide. If you want the nanosecond parameter tables side by side, they're on the QN-03 and QE-01 pages, and we'll tell you when the right answer is a machine we don't sell. Send us the caseload and ask - that conversation is free.
Written by the Pmise applications engineering team. Pulse-width figures were checked against the QN-03 and QE-01 acceptance test records. Clinical outcome figures are quoted from the peer-reviewed studies listed below and are not our own data.
Frequently asked questions
Is a nanosecond Q-switched laser obsolete?
No. It remains the standard tool for epidermal and dermal pigment, and it still clears tattoos - the comparison studies show it working, just less efficiently per session than a picosecond pulse on dense ink. Obsolete would mean it stopped doing the job. It hasn't.
How much shorter is a picosecond laser in practice?
Less than the name suggests. Commercial dermatology systems marketed as picosecond typically deliver hundreds of picoseconds rather than tens - Kono's 2020 comparison used a device running 375 and 450 ps. Against a 6 ns Q-switched pulse that's roughly a ten to fifteen fold reduction, not a thousand-fold one.
What single question exposes a false picosecond claim?
Ask for the measured pulse duration at each wavelength, with the oscilloscope trace and the measurement convention. Then check it against the claimed single-pulse energy and peak power. Numbers that don't reconcile, or a supplier who won't produce the trace, answer the question for you.
Do you sell a picosecond machine?
No. Our Q-switched line is nanosecond only, and we'd rather say that up front than imply otherwise on a spec sheet. If your caseload genuinely needs a shorter pulse, we'll say so, and you should source it elsewhere.
Will a picosecond laser prevent hyperpigmentation?
It won't. Post-inflammatory hyperpigmentation was reported across both picosecond and nanosecond arms in the 2020 Asian tattoo cohort, and paradoxical darkening appeared at the same low rate with every laser type tested. Screening, conservative test shots and honest aftercare do more for that risk than pulse width does. Anything on the skin that looks atypical gets referred to a physician, not treated.
References
- Ross V, Naseef G, Lin G, et al. Comparison of responses of tattoos to picosecond and nanosecond Q-switched neodymium:YAG lasers. Archives of Dermatology. 1998;134(2):167-171.
- Lorgeou A, Perrillat Y, Gral N, Lagrange S, Lacour JP, Passeron T. Comparison of two picosecond lasers to a nanosecond laser for treating tattoos: a prospective randomized study on 49 patients. J Eur Acad Dermatol Venereol. 2018;32(2):265-270.
- Kono T, Chan HHL, Groff WF, et al. Prospective Comparison Study of 532/1064 nm Picosecond Laser vs 532/1064 nm Nanosecond Laser in the Treatment of Professional Tattoos in Asians. Laser Ther. 2020;29(1):47-52.
- Freedman JR, et al. Picosecond lasers: the next generation of short-pulsed lasers. Seminars in Cutaneous Medicine and Surgery. 2014;33(4):164-168.
- 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 surgical, cosmetic, therapeutic and diagnostic laser equipment (IEC Webstore)
- US FDA 510(k) Premarket Notification Database (searchable by device name and applicant)