As a core device, laser diode is widely used in daily life, so what are the common wavelengths of laser diode? Let's take a look at it together.

Visible light band: 400 nm-700 nm

This part of the laser is "visible" and is mainly used in positioning, display, detection and other equipment.

1. Violet/blue light (405nm, 450nm, 488nm)

This kind of wavelength belongs to short wave, and the energy in visible light is relatively high.

405nm is often used for UV curing, optical disk reading and writing, microscopic detection, etc.

450nm blue laser, such as laser projector, laser display and blue laser engraving machine, will be used.

2. Green light (515nm, 520nm, 532nm)

The visibility of green light is very high, and it looks brightest to the naked eye, so it is widely used in rangefinders, level meters and indicators.

In the past, many people used red light to measure distance, which was almost invisible under strong light. Later, after changing to green light, it can be easily identified outdoors during the day.

3. Red light (635nm, 650nm, 660nm)

Red laser diode is the most mature and common. Low price and stable performance.

635nm has high brightness and pure color, and is commonly used in laser pens and scanners.

650nm and 660nm are mostly used in positioning, printers and optical communication.

I remember an old customer made in barcode scanner, which has been used since the early 650nm red light, because the wavelength is stable, the supply is mature and the cost is controllable.

Near infrared band: 780 nm-980 nm

This kind of wavelength laser is basically invisible to human eyes, but it has high energy and strong penetration, and is the most commonly used wave band in industrial and medical equipment.

1. 785nm、808nm

These two bands are the most common in laser beauty, infrared illumination and marking machines.

808nm laser diode is especially classic, and it is the industry standard wavelength when used in hair removal instrument. Because it has concentrated energy, good absorption effect on hair follicles and is not easy to burn the skin.

2. 850nm、880nm、905nm、940nm

These bands are common in sensors, ranging and infrared fill light.

For example, laser radar of cars and 3D face recognition of mobile phones are inseparable from VCSEL or EEL laser diodes with these wavelengths.

Far infrared band: 1300 nm-1550 nm

This part of the wavelength is mainly used for optical communication and industrial detection.

1310nm and 1550nm are the standard wavelengths of optical fiber communication, because the transmission loss of optical fiber is the smallest at these two points. It is also used in laser ranging, gas detection and other fields. The laser diode with this wavelength is generally made of InGaAsP material, which is relatively expensive, but its performance is very stable.

From a technical point of view, wavelength is not seen alone, but linked to material, power, packaging and use.

Like structured light and 3D recognition, it is inseparable from the 940nm； of VCSEL structure;

Do industrial marking, hair removal instrument, often choose 808nm；;

For projection and display, 450nm blue light or 520nm green light is valued.