The defocus mode of a CO2 laser is primarily utilized to lower energy density by increasing the laser's spot diameter. By expanding the beam to a width of 1 to 5 mm, the system distributes thermal energy over a larger surface area rather than concentrating it at a single point. This modification transforms the laser from a cutting instrument into a resurfacing tool, enabling the precise, layer-by-layer vaporization required for treating large superficial lesions without damaging deeper tissue.
By broadening the laser beam, defocus mode lowers the energy concentration per unit area to prevent deep pitting. This ensures ablation is restricted to the epidermis, allowing for safe, uniform removal of widespread lesions while minimizing the risk of scarring.
The Mechanics of Energy Distribution
Controlling Energy Density
The core principle of defocus mode is the manipulation of the beam's focal point. By moving the focal point away from the tissue surface, the spot diameter increases.
This increase in diameter effectively reduces the energy density (fluence). Instead of a high-intensity beam designed to incise, the energy is spread out to gently vaporize surface cells.
Layer-by-Layer Ablation
This reduced intensity allows for a "painting" technique rather than an excision technique.
Clinicians can remove tissue in controlled, thin increments. This is particularly effective for lesions like sebaceous hyperplasia or seborrheic keratosis, where the goal is to plane the lesion down to the skin's surface level.
Clinical Advantages for Large Lesions
Preventing Deep Pitting
The most significant risk in treating large areas with a focused beam is accidental deep tissue penetration.
A focused beam cuts vertically. A defocused beam ablates horizontally. This geometry prevents the formation of deep pits or "craters" in the skin, which are the precursors to permanent scarring.
Uniform Resurfacing
Large-area lesions require a consistent depth of removal across the entire treatment zone.
Defocus mode provides a wider coverage area per pulse. This facilitates smoother transitions between treated and untreated skin, resulting in a more uniform aesthetic outcome compared to using a narrow, focused beam.
Complementary Technologies
Thermal Damage Control
While defocus mode manages depth, combining it with ultra-short pulse widths (microseconds) manages heat transfer.
High peak power with short duration vaporizes tissue moisture instantly. This occurs faster than the time required for heat to conduct into surrounding tissue (thermal relaxation time), minimizing collateral damage and speeding up healing.
Automated Consistency
Manual defocusing relies on the operator's hand distance, but Scanning CO2 systems automate this process.
Scanners deliver the beam in a precise pattern, ensuring the ablation level is perfectly uniform. This reduces side effects like edema and erythema by eliminating the inconsistencies inherent in manual handpiece operation.
Understanding the Trade-offs
Limited Penetration Depth
The primary strength of defocus mode is also its main limitation: lack of depth.
Because the energy is dispersed, this mode is ineffective for cutting or excising deep dermal tumors. Attempting to reach deep targets with defocus mode leads to excessive thermal buildup at the surface rather than clean incision.
Operator Dependency
In manual systems, "defocus" is often achieved by physically pulling the handpiece back from the skin.
If the operator's hand is unsteady, the distance fluctuates. This causes the spot size—and therefore the energy density—to vary unpredictably, potentially leading to uneven ablation depths.
Making the Right Choice for Your Goal
To achieve the best clinical outcomes, you must match the laser configuration to the pathology:
- If your primary focus is excision or deep cutting: Use a focused beam to maximize energy density for clean, vertical incisions.
- If your primary focus is treating large, superficial lesions: Use defocus mode to lower energy density and enable safe, layer-by-layer resurfacing.
- If your primary focus is minimizing recovery time: Combine your ablation settings with ultra-short pulse widths to limit thermal damage to healthy tissue.
Defocus mode effectively repurposes the CO2 laser from a surgical scalpel into a precision sander, prioritizing tissue preservation over cutting power.
Summary Table:
| Feature | Focused Mode | Defocused Mode |
|---|---|---|
| Energy Density | High (Concentrated) | Low (Dispersed) |
| Beam Diameter | Narrow (< 1mm) | Wide (1-5mm) |
| Ablation Path | Vertical (Cutting) | Horizontal (Resurfacing) |
| Primary Use | Excision & Deep Incisions | Superficial Lesions & Planing |
| Tissue Impact | Deep tissue penetration | Epidermal vaporization |
Elevate Your Clinic’s Precision with BELIS Medical Systems
At BELIS, we specialize in professional-grade medical aesthetic equipment designed exclusively for clinics and premium salons. Our advanced CO2 Fractional Laser systems feature precision scanning technology and ultra-short pulse modes, allowing you to master defocus ablation for flawless superficial treatments while minimizing thermal damage.
From high-performance Diode Hair Removal and Pico lasers to HIFU, Microneedle RF, and Body Sculpting solutions (EMSlim, Cryolipolysis), our portfolio empowers your practice with reliability and superior clinical outcomes. We also provide specialized care devices including Hydrafacial systems, skin testers, and hair growth machines to complete your service menu.
Ready to upgrade your technology and deliver exceptional results to your patients?
Contact BELIS Today to Request a Quote
References
- Sahar Abdualkader Ismaeel, Alaaaldeen Alani. Carbon Dioxide Laser in the Treatment of Oral and Craniofacial Soft Tissue Lesions, Pros and Cons. DOI: 10.37506/ijfmt.v14i4.12156
This article is also based on technical information from Belislaser Knowledge Base .
Related Products
- Fractional CO2 Laser Machine for Skin Treatment
- Fractional CO2 Laser Machine for Skin Treatment
- Pico Laser Tattoo Removal Machine Picosure Picosecond Laser Machine
- Trilaser Diode Hair Removal Machine for Beauty Clinic Use
- Diode Laser SHR Trilaser Hair Removal Machine for Clinic Use
People Also Ask
- Is CO2 laser for all skin types? A Critical Guide to Skin Type Safety and Risks
- Why am I not seeing results after a CO2 laser? Your Patience is the Key to Long-Term Skin Rejuvenation
- How often should you do fractional CO2 laser? The 4-6 Week Rule for Optimal Results
- How does fractional CO2 laser work? The Science Behind Powerful Skin Renewal
- What will my face look like after a CO2 laser? Your Complete Recovery Timeline
