We all know that particle counters are the most common in daily life, and their position in industry and civil use is unshakable. Many people are curious about which band of products are used in laser diodes. Today, Xiaobian will give you an analysis.

The most commonly used band of particle laser module is red light or near infrared band, that is, from 630nm to 850nm. The light in this range has strong penetration and good scattering characteristics, and can also give consideration to cost and stability.

Many air detectors in the market, such as Xiaomi air purifier and industrial environmental monitoring equipment, commonly use 650nm red laser diode. The red light in this band is visible, which is convenient for debugging, and it can produce obvious scattering signals when it meets particles in the air, so the photoelectric sensor can capture the changes more easily.

Some high-end monitors, such as those used for laboratory or industrial smoke monitoring, will use near-infrared laser diodes of 780nm, 808nm or even 850nm. Although this kind of light is invisible to the naked eye, it has the advantages of less interference from ambient light and more stable signal, which is especially suitable for long-term work in dusty and humid environment.

You may ask, then why not use a shorter wavelength, such as blue light or green light? In fact, it is not impossible, but unnecessary. Blue light scatters more strongly and can detect finer particles in theory, but laser diodes have high cost, short life and are easily affected by temperature. For most PM detection, red light or near infrared is accurate and economical enough.

Therefore, what band to choose for the particulate laser module mainly depends on the detection requirements, environmental conditions and cost budget.