WHAT ARE LASERS?

What is a Laser?

LASER stands for Light Amplification by Stimulated Emission of Radiation.

A laser is a device that produces a highly focused beam of coherent light through a process known as optical amplification. This light is a form of electromagnetic radiation, composed of tiny particles called photons that travel in organized waves.

Because laser light is concentrated, precise, and consistent, it can be safely harnessed in medical aesthetics to target specific skin structures without damaging surrounding tissue.

By directing this controlled beam of light, practitioners can treat a wide range of skin conditions and cosmetic concerns, including:

• Permanent hair reduction

• Skin rejuvenation and resurfacing

• Treatment of vascular and pigmented lesions

• Correction of unwanted imperfections

Laser technology allows for precision, safety, and predictable results, making it one of the most effective tools in modern aesthetic science. Understanding How Lasers Work

A laser is a device that produces an intense, focused beam of light. The term LASER stands for Light Amplification by Stimulated Emission of Radiation—each word describing part of how this remarkable technology works:

• Light is energy made up of tiny particles called photons. It’s what allows us to see, like sunlight or a flashlight beam.

• Amplification means strengthening that light—turning a small amount into a powerful, concentrated beam.

• Stimulated Emission is the process where photons trigger atoms to release identical photons, all moving in sync—like perfectly timed dancers.

• Radiation refers to energy traveling in waves. In a laser beam, these waves align perfectly, creating a coherent, organized stream of light energy.

In essence, a laser takes ordinary light and transforms it into a precisely organized, high-energy beam—a tool powerful enough for use in medicine, science, and beauty treatments.

Let’s start off with the real basics The Nature of Light

For centuries, scientists have explored one of physics’ greatest mysteries — what exactly is light?

In 1864, Scottish physicist James Clerk Maxwell proposed that electric and magnetic fields are interconnected, forming electromagnetic waves. When he calculated their speed, he discovered it matched the speed of light, confirming that light behaves as a wave.

Later, in the 19th century, Albert Einstein expanded this understanding by revealing light’s dual nature — that it behaves as both a wave and a particle. He showed that light consists of photons, tiny particles of energy that travel in a wave-like pattern.

This discovery became the foundation of modern optics and laser technology, where light’s dual nature allows it to be amplified, focused, and precisely controlled. The Electromagnetic Spectrum

The Electromagnetic Spectrum represents the full range of light and radiation that exists in the universe. It’s called electromagnetic because it’s made up of oscillating electric and magnetic fields, composed of massless photons that travel in wave-like patterns.

These waves vary in frequency (how often they oscillate) and wavelength (the distance between wave peaks).

• Gamma rays have the highest frequency and shortest wavelength.

• Radio waves have the lowest frequency and longest wavelength.

This spectrum includes both the visible light we can see and the invisible radiation that surrounds us — from radio signals to X-rays. In aesthetic medicine, we selectively use specific wavelengths from this spectrum to rejuvenate the skin, reduce hair growth, and promote healing.

Ionizing vs. Non-Ionizing Radiation Not all radiation is the same. The key difference lies in how much energy each type of wave carries.

• Ionizing Radiation (such as gamma rays, X-rays, and part of ultraviolet light) carries very high energy. It’s powerful enough to break chemical bonds within atoms — including those in DNA. This can cause cell damage, mutations, or even cancer.

• Non-Ionizing Radiation (including visible light, infrared, microwaves, and radio waves) carries much lower energy. Instead of breaking molecules apart, it simply heats and energizes atoms and tissues.

Because lasers produce non-ionizing radiation, they operate safely within this beneficial range. The energy they emit can be precisely tuned to stimulate collagen, target pigmentation, or reduce unwanted hair — all without damaging the DNA of surrounding cells.

In aesthetics, our focus is on  “Visible Light” and a bit into the “ near-Infrared light.” Visible light is light that can be detected by the naked human eye. It ranges from 400 to 750 nanometers. Near- Infrared light is light that exists but is invisible to our eyes. These wavelengths range from 750 to 2,500 nanometers and have a major influence on the depth of penetration in the skin. Violet and blue light have shorter wavelengths; therefore, they penetrate more superficially. These wavelengths range from 415 to 530 nanometers.

We use these short wavelengths to treat mild to moderate acne, superficial pigmentation, or superficial vascular lesions. Since these wavelengths are short, they penetrate closer to the surface of the epidermis. Comparatively, red light has longer wavelengths, therefore it penetrates deeper into the tissue. Red light ranges from approximately 620 to 750 nanometers. Near-infrared light ranges from 750 to 2,500 nanometers. We use red light and a small portion of the infrared light to cause thermal damage to hair follicles when treating for hair removal.

By understanding and selecting the correct wavelength range, practitioners can customize treatments to precisely target skin concerns at the appropriate depth — ensuring safety, efficacy, and optimal results.

Types of Laser Treatments: Ablative vs. Non-Ablative

Most aesthetic laser treatments fall into two main categories: Ablative and Non-Ablative.The difference lies in how deeply the laser interacts with the skin and the degree of recovery required afterward.

Ablative treatments are more intensive and involve removing or “vaporizing” the outer layers of the skin to stimulate a powerful healing response. Because these lasers penetrate deeper, they come with longer downtime and recovery, but also produce dramatic improvements in skin tone, texture, and rejuvenation.

Common Ablative Lasers:

• Erbium:YAG (2,940 nm): Gently removes superficial and moderately deep lines with minimal thermal damage.

• CO₂ Laser (10,600 nm): Penetrates deeper into the dermis, vaporizing damaged tissue and triggering significant collagen remodeling.

These wavelengths correspond to high water absorption peaks—since water is the skin’s primary chromophore—allowing the laser to vaporize tissue effectively.As the skin heals, it generates new collagen and smoother, healthier layers.Ablative lasers are ideal for treating deep acne scarring, wrinkle reduction, and advanced signs of aging.

Non-ablative treatments work beneath the skin’s surface, gently heating targeted chromophores (such as melanin or hemoglobin) without damaging the outer layer.This creates a controlled thermal injury that stimulates collagen and elastin production over time.

Because the epidermis remains intact, non-ablative procedures involve minimal to no downtime, though multiple sessions are often required to achieve optimal results.

Common Non-Ablative Applications:

• Permanent hair reduction

• Treatment of vascular or pigmented lesions

• Skin tightening and collagen rejuvenation

In general, shorter wavelengths act near the skin’s surface, while longer wavelengths penetrate deeper into the tissue.

However, Erbium:YAG and CO₂ lasers are special exceptions.Despite their long wavelengths, they don’t bypass the surface to heat deeper layers. Instead, they are highly absorbed by water, resulting in a surface-level ablative effect that vaporizes tissue rather than simply heating it.

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