Which of the following is NOT one of the three properties of laser light?

Monochromatic, coherent, and collimated are the three fundamental properties of laser light that distinguish it from other light sources.

Monochromatic means that laser light consists of a single wavelength, resulting in a uniform color. This property is essential for various applications in medicine, manufacturing, and communication, as it allows for precise targeting and minimal interference.

Coherent refers to the light waves being in phase with one another, meaning that they share a constant phase relationship. This quality enhances the laser's ability to focus energy tightly and produce highly directed beams.

Collimated describes how laser light travels in parallel rays with very little divergence, allowing it to maintain its intensity over long distances. This property is crucial in applications where the precision of the light's focus and energy delivery is necessary.

The term "irregular" does not fit with the properties of laser light, as it implies randomness and lack of order, which contradicts the characteristics of lasers that depend on precise control of wavelength and phase coherence. Thus, identifying "irregular" as not being one of the core properties of laser light is accurate.