How light
heals skin.
A visual, easy-to-follow guide to dermatology and the lasers doctors use to treat hair, pigment, scars, blood vessels and tattoos — explained from the very basics.
- 0bite-sized lessons
- 0laser applications
- 0glossary terms
Laser & dermatology, explained simply
Dermatology is the branch of medicine that cares for the skin, hair and nails. Lasers are one of its most powerful tools — devices that produce a pure, focused beam of a single colour of light.
Different parts of your skin — brown pigment (melanin), red blood (haemoglobin), water, even tattoo ink — soak up different colours of light. By choosing the right laser, a doctor can heat only the target, like a hair root or a dark spot, while the skin around it stays safe. This clever idea is called selective photothermolysis.
Read the fundamentals guideThe target
Three layers — epidermis, dermis, hypodermis — each with things lasers can aim at.
The tool
A laser beam is one wavelength, perfectly in step, travelling in a straight line.
The action
The target absorbs light, turns it into heat or a shock wave, and is damaged.
The result
The body clears the damaged bits and builds fresh collagen and skin.
Six short modules, from zero to confident
About 18 minutes in total. Read in order, or jump to what you need.
Skin basics
Layers of the skin, melanin, collagen and blood vessels.
3 min readWhat is a laser?
LASER explained, wavelength and the 3 special properties.
4 min readHow lasers treat skin
Chromophores and selective photothermolysis.
4 min readTypes of lasers
Ablative, non-ablative and fractional lasers.
3 min readSafety & skin types
Laser classes, eye safety and the Fitzpatrick scale.
2 min readTest yourself
A short quiz to check what you have learned.
2 min readHow every skin laser works — in 3 steps
Think of a black T-shirt on a sunny day: it gets hotter than a white one because dark colours absorb more light. Lasers use the same trick, but with a single, carefully chosen colour.
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1
Aim
Choose a wavelength that the target absorbs strongly and that reaches the right depth.
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2
Absorb
The target (chromophore) soaks up the light and turns it into heat — in a pulse short enough that heat can’t spread.
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3
Heal
The body’s healing response removes the damaged target and builds new collagen over weeks.
Where lasers are used in dermatology
Laser Hair Reduction
How lasers heat the pigment in hair roots so they stop producing thick hair.
Read the topic IntermediatePigmentation & Melasma
Breaking up extra melanin in sun spots, freckles and melasma.
Read the topic IntermediateSkin Resurfacing
Vaporising thin layers of skin to smooth wrinkles and texture.
Read the topic IntermediateAcne Scars
Remodelling pitted scars by rebuilding collagen underneath.
Read the topic IntermediateVascular Lesions
Closing tiny visible blood vessels — redness, rosacea, birthmarks.
Read the topic BeginnerTattoo Removal
Shattering ink particles so the immune system can clear them.
Read the topic AdvancedVitiligo & Psoriasis
Targeted ultraviolet light that calms overactive immune responses.
Read the topic BeginnerSkin Rejuvenation
Gentle, non-ablative heating that boosts collagen with no downtime.
Read the topicEvery wavelength has a purpose
Pick a laser to see what it targets, how deep it reaches into the skin, and where its light sits on the spectrum. Notice: longer infrared wavelengths (except those absorbed by water) travel deeper.
Diode
nm
- Laser type
- Main target
- Used for
- Relative depth
Pick a skin problem. Find its laser.
Every treatment starts with one question: what is the target? Choose a problem to see which chromophore absorbs the light, which laser is typically used, and why.
Then try changing the skin type to see how safety thinking changes.
Choose a skin problem
Skin type (Fitzpatrick scale)
Choose a skin problem above to see the answer ✨
From an idea to everyday medicine
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1917
The idea
Albert Einstein describes “stimulated emission” — the physics that makes lasers possible.
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1960
First laser
Theodore Maiman builds the first working laser using a ruby crystal (694 nm red light).
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1963
Lasers meet skin
Dermatologist Dr. Leon Goldman begins studying lasers on skin — he is often called the “father of laser medicine”.
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1983
The big breakthrough
Anderson & Parrish publish selective photothermolysis: how to heat only a chosen target without harming nearby skin.
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2004
Fractional lasers
Fractional photothermolysis treats tiny columns of skin at a time, so healing becomes much faster.
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2010s
Picosecond era
Ultra-short picosecond pulses arrive for tattoos and pigment — shattering particles with less heat.
Questions students often ask
Still curious? The glossary explains every key term in one line.
Is laser light the same as X-ray radiation?
No. The “radiation” in LASER just means light energy. Skin lasers use visible, infrared or ultraviolet light — they are non-ionising, which means they do not have enough energy to break DNA the way X-rays or gamma rays can. (UV lasers like the excimer are the exception that needs careful dosing.)
Why do people wear special goggles during laser treatment?
The eye focuses light onto the retina, concentrating it many times over. Even a reflected medical laser beam can permanently damage vision, so everyone in the room wears goggles rated for that exact wavelength.
Why are several sessions usually needed?
Each session treats only part of the target — for example, only hairs in the growth phase, or only some of the ink or pigment. The body also needs weeks to clear debris and build new collagen between sessions.
What is the difference between IPL and a laser?
A laser gives one single wavelength in a focused beam. IPL (Intense Pulsed Light) is a flash lamp that gives a broad range of wavelengths, filtered to remove some. IPL is versatile but less precise than a laser.
Why is skin colour so important in laser treatment?
Melanin in the skin surface can absorb laser energy meant for a deeper target. In darker skin this can cause burns or pigment changes, so longer wavelengths (like 1064 nm), lower energies and skin cooling are used.
How do you become a dermatologist in India?
After MBBS (5.5 years including internship), doctors clear NEET-PG and complete a 3-year MD in Dermatology, Venereology & Leprosy (or DNB). Laser skills are learned during residency and through fellowships.
Key papers & trusted sources
Want to cite something in a project or go deeper? Start with these landmark papers and free resources.
- [1]Maiman TH. Stimulated optical radiation in ruby.Nature, 1960; 187: 493–494The first working laser.
- [2]Anderson RR, Parrish JA. Selective photothermolysis: precise microsurgery by selective absorption of pulsed radiation.Science, 1983; 220: 524–527The core principle behind skin lasers.
- [3]Manstein D, et al. Fractional photothermolysis: a new concept for cutaneous remodeling using microscopic patterns of thermal injury.Lasers in Surgery and Medicine, 2004; 34: 426–438The birth of fractional lasers.
- [4]DermNet — skin conditions & laser treatment topicsdermnetnz.orgFree, reliable patient & student resource.
- [5]American Academy of Dermatology — Lasers & lightsaad.orgPublic education from dermatologists.
Test what you’ve learned
Six quick questions on skin, lasers and how they work together.