Picosecond laser, why has it been burning for so long? - lefislaser

Mar 2, 2022Translation missing: en.blog.post.reading_time

Picosecond Laser: How It Works, Wavelengths, Indications and Recovery

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A picosecond laser is a medical aesthetic laser that fires pulses shorter than one nanosecond, measured in trillionths of a second, to fragment tattoo ink and pigment mainly through a photomechanical pressure wave rather than heat alone.

The pulse is the selling point. At a few hundred picoseconds per shot, the heat barely has time to leave the ink particle. It cracks. The dermis next to it mostly doesn’t cook.

Tattoos came first; look at the head-to-head papers and most of them still are about tattoos. Lentigines and nevus of Ota got added after that, plus the rest of the benign pigment, and once fractional tips showed up the same machine started doing acne scars and texture too.

None of that makes the machine smart. Someone still has to pick the wavelength, judge the skin type and notice when a “sun spot” looks wrong, and in our experience supplying clinics, that person matters more than the spec sheet.

What Is a Picosecond Laser? The Short Version

How we’d put it to a patient at the front desk: a picosecond is one trillionth of a second, and the aesthetic units we see mostly fire pulses of somewhere around 300 to 900 of those. Q-switched units count in nanoseconds instead, and that works out to something like ten to a hundred times longer per shot.

Same joules, shorter window. The particle can’t vent the stress in time and snaps into smaller bits, and the body hauls those away over the next few weeks.

Picosecond vs. Q-Switched Lasers at a Glance

Feature	Picosecond laser	Q-switched (nanosecond) laser
Pulse length	<1 ns (300–900 ps typical)	~5–50 ns
Pigment disruption	Mostly pressure wave	Mostly heat
Ink fragments	Smaller	Larger
Head-to-head trials	Equal or better in several split-lesion studies	Decades of data
Fractional handpiece	Common	Uncommon
Purchase price	Higher	Lower

Not every clinic needs one. A practice that mostly treats black amateur tattoos and lentigines in lighter skin can run a profitable Q-switched service, and we would rather tell a buyer that than sell them the wrong machine.

How a Picosecond Laser Works

[IMAGE-01 placeholder] Alt text: Diagram comparing photothermal and photomechanical laser-tissue interaction

Selective Photothermolysis: The Starting Point

Most of what we know about aiming lasers at pigment goes back to a 1983 paper in Science by Anderson and Parrish, which set the basic rule that you choose a wavelength the target soaks up and keep the pulse shorter than the time it takes that target to lose its heat.

Ink is the awkward target. Lots of tattoo particles measure well under a micron. For something that small, 10 nanoseconds is slow. It’s one reason a nanosecond laser can stall on a stubborn tattoo around session five or six.

The Photomechanical Effect

Shorten the pulse past a certain point and the particle has no time to relieve its internal stress. It fractures. Macrophages and lymph drainage clean up afterward, over weeks.

Ross’s group checked this back in 1998 (Archives of Dermatology). Sixteen black tattoos, each split down the middle: 35-picosecond Nd:YAG on one part, 10-nanosecond on the other. The picosecond side lightened significantly more in 12 of 16 tattoos.

Laser-Induced Optical Breakdown With Fractional Optics

A fractional handpiece breaks the beam into a grid of microbeams. In a 2016 histology study, Tanghetti treated skin with a picosecond alexandrite laser and a fractional lens array and found small vacuoles inside the epidermis, the result of laser-induced optical breakdown (LIOB).

The stratum corneum stayed largely intact. The remodeling that follows is the basis for fractional pico laser facial rejuvenation and pico laser for acne scars.

Short Pulses Are Not Heat-Free

Thermal spread drops, but anyone who has watched a patient’s cheek go pink and warm ten minutes after a session knows it does not disappear, and at high fluence an epidermal burn is still on the table.

Picosecond Laser Wavelengths Compared

[IMAGE-02 placeholder] Alt text: LEFIS picosecond laser handpiece with interchangeable wavelength tips

Pulse length is the how. Wavelength is the where. Swap the tip on a picosecond platform and you’re effectively holding a different laser.

Wavelength	Source	Targets	Typical uses	Notes
532 nm	Doubled Nd:YAG	Melanin, Hb; red/orange/yellow ink	Freckles, lentigines, warm ink	Shallow. PIH risk up in IV–VI
730 / 785 nm	Converter tip, varies by platform	Blue/green ink, some pigment	Blue and green ink	Ask what reaches the skin, not the cavity
755 nm	Alexandrite	Melanin; black, blue, green ink	Tattoos, Ota, fractional work	Melanin grabs it; go slow in darker skin
1064 nm	Nd:YAG	Black ink, dermal pigment	Black tattoos, ABNOM, Ota, low-fluence melasma work	Deepest reach, lowest melanin uptake

Matching Wavelength to Tattoo Ink Color

Black ink is the forgiving one and 1064 nm handles most of it. Red, orange and yellow, 532 nm.

Blue and green used to be the colors nobody wanted to promise on. Then Brauer’s 2012 series: 12 tattoos with blue or green ink, a 755 nm picosecond laser, and all 12 cleared at least 75% of those colors in one or two sessions. No control group, and twelve tattoos isn’t many, but distributors still mention that paper to us.

Picture a sleeve that has black linework, some red lettering and green shading in it. You’d want two wavelengths at the very least for that one, so check what’s really mounted on your machine before you tell anyone how many sessions it’ll take.

Matching Wavelength to Skin Type

In darker skin, epidermal melanin eats a good share of a 532 or 755 pulse up top. Less of it gets down to the pigment you actually wanted.

Types IV to VI: open with 1064. Keep 532 and 755 for particular lesions, after a test spot. Our CO2 laser on dark skin guide runs through the same problem with ablative lasers.

Picosecond Laser Indications: Where the Evidence Stands

Wu, Goldman, Wat and Chan went through 200-plus studies for Lasers in Surgery and Medicine and landed on safe and effective. Fine. Open the actual trials, though, and some indications sit on solid RCTs while others sit on a dozen patients.

Indication	Evidence	Caution
Tattoo removal	Original use; most comparative data	Multiple sessions; some inks won’t clear
Solar lentigines	Split-face RCT, 14 Asian patients; >50% better on 85.7% of pico sides vs 57.2% QS at 6 mo	Tiny trial; sun brings them back
Nevus of Ota	56-pt split-lesion RCT vs QS alex: clearer, 5.26 v 5.87 sessions, less pain	PIH 26 v 34%; hypo 21 v 47%
Melasma	2023 meta-analysis (6 RCTs): 1064 lowered MASI/mMASI; 755 ≈ topicals	I² 70%; it comes back
Café-au-lait macules	Mixed	Recurs; test spot
Acne scars, texture	Fractional tips, several studies	Slow, series-based change
Photoaging, pores	Modest	Not ablative-level

Lesions to Leave Alone

No diagnosis, no laser. Hit an early melanoma and you can bleach the part you see, leave the rest, and push the diagnosis back by months.

Ragged edge. Two or three colors. Changed lately, bled, or the patient has no idea how long it’s been there. Refer it. A biopsy can settle it.

Melasma Needs a Different Conversation

We used to list melasma next to freckles on this page. Wrong call. Hormones, UV, visible light, vessels, inflammation: they all feed it, and one keen pass can send a patient home darker than she arrived.

Treating it anyway? 1064 nm, low fluence, sunscreen she’ll actually wear, a topical regimen. And say out loud at the first visit that it will probably come back. Our article on CO2 laser for melasma gets into why heat-heavy approaches are riskier still.

How Many Sessions Does Picosecond Laser Treatment Take?

A fixed number at consultation is a guess. Ink density, color, depth, skin type, the indication itself, and how this particular person heals all move it.

Tattoos need several visits spaced weeks apart, since the ink has to clear and the skin has to recover between passes, and the American Academy of Dermatology makes the point that a lot of patients give up too early. Our tattoo removal healing stages guide covers what happens in between.

In the nevus of Ota trial, the picosecond side averaged 5.26 sessions. Superficial lentigines often need fewer.

How Long Do Results Last?

Removed ink does not return. Lentigines and freckles can, with continued sun exposure. Melasma usually does.

Write sun protection into the treatment plan, not only the aftercare sheet. Earlier versions of this page said results “last one to two years.” We found no evidence for that figure and removed it.

Why Does It Feel Like Burning After Picosecond Laser?

[IMAGE-03 placeholder] Alt text: Clinician applying a cool compress to a patient’s cheek after laser treatment

Some burning after a picosecond session is normal. Patients call it a fresh sunburn. By evening it’s usually quieter; a day or two and it’s done.

Worry about the patient who says day two feels worse than day one. Or who mentions blisters, weeping, redness spreading out from the edge. Same-day visit for those.

What’s Normal Right After a Session

Expect the skin to be red and a bit puffy, warm and tender to touch, which happens almost every time. Tattoo sessions add the white frosting that’s gone in minutes, then pinpoint bleeding or a thin crust.

The AAD’s tattoo removal page says you can get redness, swelling and some blistering, and that any light or dark patches usually fade within 6 to 12 months.

When the Burning Hangs Around

Fluence too high for the patient. A setting that suits a type II forearm can burn a type V forearm, or a type II forearm with a two-week tan.
Stacked pulses. Repeated passes over one spot let heat build.
Wavelength mismatch. 532 or 755 on a type V cheek.
Barrier irritation. Tretinoin she forgot to mention, or a glycolic toner, a vitamin C serum, a moisturizer with fragrance in it.
Heat and sun. Hot yoga at 7 a.m. Long shower. Window down on the drive home.

When Burning Is Normal and When to Call the Clinic

What the patient notices	Likely meaning	What to do
Warmth, redness, mild sting fading over hours	Normal	Follow written aftercare
Pinpoint bleeding, fine crusts, brief frosting	Normal after tattoo work	Leave crusts alone
Burning worse after day one	Possible epidermal injury	Call the clinic same day
Blisters, raw skin, oozing	Possible burn	Call the clinic; do not pop
Spreading redness, pus, fever	Possible infection	Prompt medical review
Face or throat swelling, breathing trouble, hives	Possible allergic reaction	Emergency care

General Aftercare Principles

The clinic’s written instructions take priority. Common points:

Cool compress for short periods, if the clinic approves; never bare ice
No picking, rubbing or peeling
Stop actives until the clinic clears them
No saunas, hot water or hard exercise while it still burns
Sun protection, and for tattoo-removal sites the AAD suggests keeping them covered from the sun for three months

For Clinics: Cutting Down the Day-Three Calls

A day-three phone call about burning usually starts at the consultation. Fix it there.

Record the Fitzpatrick type and ask about recent tanning
Test spot in higher-risk skin
Start conservative; adjust to the endpoint you actually see
Give written aftercare with an after-hours number
Ring the higher-risk patients yourself by day three rather than waiting for them to ring you

Who Makes a Good Picosecond Laser Candidate

Easiest case we can think of: a lesion a dermatologist already called benign, or an old tattoo the person is fed up with. They know it’s going to take more than one visit. And they’ll actually skip the beach for a bit.

Defer or discuss first:

Pregnant or nursing; the AAD says wait on tattoo removal
Anything infected, inflamed or open at the site
Tanned now, or Cancún in three weeks
Any undiagnosed or changing pigmented lesion
Keloids, marked PIH, or slow wound healing in the history
On a photosensitizer, or isotretinoin recently (clinician’s call)
Reduced immune function, which per the AAD can slow tattoo clearance

The old version of this page told patients to avoid spicy food and to schedule around their menstrual cycle. Neither has evidence behind it. A proper medication review does more.

Choosing a Picosecond Laser Machine: What Clinics and Distributors Should Check

[IMAGE-04 placeholder] Alt text: LEFIS C16 picosecond laser system in a clinic treatment room

Two machines can print the same wavelength list on the brochure and put out very different energy at the tip, so ask for measurements rather than labels, and be a little suspicious of anyone who can’t produce them.

FDA Rules for Picosecond Lasers in the U.S.

Dermatologic lasers sit in Class II with the FDA, under 21 CFR 878.4810. What that means day to day is a 510(k) clearance tied to one specific model and the indications listed on it. On top of that, any laser product has to pass the radiation-safety standard in 21 CFR 1040.10.

Ask the supplier for the 510(k) number, then type it into the FDA database yourself. Five minutes, maybe less. Importers will also want our medical device compliance checklist.

Technical Specifications Worth Verifying

Check	Why
Measured pulse duration at each wavelength	Some systems are only picosecond at 1064 nm
Peak energy per pulse, spot sizes	Caps the ink density you can clear
Source of each wavelength	Converter tips often deliver less
Energy stability over a full session	Drift means unpredictable results
Beam profile, fractional tips	Hot spots raise burn risk
Cooling, service, spare parts	Downtime costs more than parts

Our picosecond laser machine supplier checklist walks through the questions, and the picosecond laser energy stability test is worth running before you sign for delivery. Once it’s installed, picosecond laser machine maintenance covers the routine.

Cost and Ownership

Branded platforms are expensive before you even count handpieces, service contracts and the weeks a machine can sit idle waiting for a part. For the numbers, see PicoSure machine cost and alternatives and the tattoo removal laser machine cost and ownership guide.

If you’re opening a tattoo removal service from scratch, budget for wavelength-rated eyewear, smoke evacuation and training too; the tattoo removal clinic startup checklist has the list.

Source Picosecond Laser Systems From LEFIS

We build picosecond laser machines here at LEFIS, the C16 picosecond laser system among them, and sell to clinics and med spas as well as distributors and OEM/ODM partners.

If you want the spec sheet, ask; it has the measured pulse duration and energy numbers in it. We’ll send the handpiece list too, and whichever regulatory papers your market asks for. Contact the LEFIS team for wholesale pricing, private label or a technical call with our engineers.

Final Takeaway

Sub-nanosecond pulses, ink broken mostly by pressure, less heat bleeding into the skin around it: that is the technology in a sentence.

The data is best for tattoos, lentigines and nevus of Ota. Melasma and skin types IV to VI call for 1064 nm, a test spot and a light hand.

A few hours of burning is expected; burning that climbs, blisters or anything that looks infected is the clinic’s job. Buying one? Get the measured pulse duration, energy and stability numbers in writing, and look up that 510(k) on your own.

FAQs

What is a picosecond laser used for?

Mostly getting rid of tattoos, plus benign pigment like solar lentigines, freckles and nevus of Ota. With a fractional tip, also acne scars, texture and photoaging. Every pigmented lesion needs a diagnosis first.

Is a picosecond laser better than a Q-switched laser?

For tattoos and some pigmented lesions, several split-lesion trials found equal or better clearance, sometimes with fewer sessions or less pain. Not for every indication, and Q-switched lasers still treat plenty of patients well.

Why does my skin still burn after picosecond laser treatment?

A few hours of sunburn-type burning is the skin’s normal reaction, and it usually settles within a day or two. If it’s getting worse, or you have blisters, oozing, spreading redness or a fever, call the clinic that treated you.

How long should redness last after pico laser?

Hours to a few days, depending on the area and settings. Crusts after tattoo work can hang around longer. Pigment changes, if they happen, can take months to fade.

Is picosecond laser safe for dark skin?

It can be, at 1064 nm with conservative settings and a test spot. 532 nm and 755 nm carry a higher risk of post-inflammatory hyperpigmentation in Fitzpatrick IV–VI skin.

Can a picosecond laser remove melasma?

It can improve it, not cure it. A 2023 meta-analysis found benefit at 1064 nm, while 755 nm did no better than topical therapy. Without ongoing sun protection and maintenance, melasma usually comes back.

How many picosecond laser sessions are needed?

Tattoos: several, weeks apart. Nevus of Ota: about five in the main comparative trial. Superficial lentigines: often fewer. The treating clinician sets the plan after seeing you.

Does picosecond laser treatment hurt?

Most people compare it to a rubber band snapping on the skin. Some comparative trials reported less pain than with Q-switched lasers. Numbing cream and cooling are common.

Which picosecond wavelength removes which tattoo colors?

1064 nm for black and dark ink. 532 nm for red, orange and yellow. 755 nm or 730–785 nm for blue and green. Multicolor tattoos usually need two or more.

Are picosecond lasers FDA cleared?

Some are, for specific indications. Clearance belongs to a model, not to picosecond technology. Check the 510(k) number and cleared indications for the exact machine.