CLT Laser Technology & Equipment 3

Question 1

Which laser type uses a gas mixture of carbon dioxide as the active medium and emits at 10,600 nm?

Accepted Answer

CO2 laser

Answer

The CO2 laser emits at 10,600 nm in the mid-infrared spectrum and is strongly absorbed by water, making it effective for tissue ablation and resurfacing.

Question 2

What property of a laser beam is described by the term 'coherence'?

Accepted Answer

All photons travel in phase with one another

Answer

Coherence means the light waves in a laser beam maintain a fixed phase relationship, enabling constructive interference and extremely focused energy delivery.

Question 3

The Er:YAG laser (2940 nm) is preferred over CO2 (10,600 nm) for superficial skin resurfacing because it:

Accepted Answer

Has 10–16× greater water absorption, allowing more precise ablation with less thermal damage

Answer

At 2940 nm, Er:YAG matches the peak absorption of water more closely than CO2, resulting in precise micro-ablation with minimal collateral thermal injury.

Question 4

Which parameter directly controls the depth of laser energy penetration into tissue?

Accepted Answer

Wavelength

Answer

Wavelength determines how deeply photons penetrate tissue because each tissue chromophore has characteristic absorption coefficients at specific wavelengths.

Question 5

A fractional laser creates an array of micro-treatment zones (MTZs) separated by untreated tissue columns. What is the primary clinical benefit of this approach?

Accepted Answer

Faster healing due to migration of cells from untreated zones

Answer

Sparing columns of untreated tissue between MTZs provides a reservoir of intact cells that accelerate re-epithelialization and collagen remodeling.

(CLT) Certified Laser Therapist Practice Test

(CLT) Certified Laser Therapist Practice Test

CLT Laser Technology & Equipment 3