Blue Lasers for Automated Organic Laser Weeding

The ever-increasing world population is driving the need for intense food production. One of the factors limiting horticultural yield is ineffective weed control and while there are methods that are widely used, they are not necessarily the best solutions. The wide-spread chemical weed removal methods raise food safety and environmental concerns, while physical weed control can decrease the crop yield by damaging the plants or other organisms that are beneficial for them.

This is where lasers come in. In the last couple of decades research has proven that laser treatment can be effectively deployed to kill weeds. And thanks to the recent developments in AI machine vision and robotics, laser weeding is becoming an extremely precise, organic, highly automated and cost-effective method.

Damaged Crops

But this technology is still fairly new and so it has its drawbacks. Most of them stem from the use of CO2 lasers, which rely on heating up the weed in order to damage its cells. This requires high optical powers, and the resulting heat can negatively impact the crop. What’s more, to reach these high powers CO2 lasers require a lot of energy due to their fairly low efficiency, and this requires the use of high-voltage generators.

Quite often the agricultural environment is arid and has a lot of dry plant parts, which in combination with high voltage increases the fire hazard. High energy also means that a lot of heat has to be dissipated, so CO2 lasers usually require the use of water cooling modules. This, along with the CO2 lasers large size, makes the system quite sizable and heavy. All these drawbacks show that there is a need to choose a more suitable type of laser for this task.

This is where the state-of-the-art blue laser technology comes into play.

Organic Automated Weed Control System with Blue Laser Shown in Action Doing Organic Laser Weeding

Research has shown that the effect lasers have on weeds depends on optical power, exposure time, spot size and most importantly, laser wavelength. Blue light is known to be highly absorbed by organic matter and such is the case with the vast majority of plants. This is due to chlorophyll used in oxygenic photosynthesis, and to be more precise, two types of chlorophyll: chlorophyll-a and chlorophyll-b. Looking at the absorption spectrum of both these pigments it becomes evident that blue light is a great match, with absorption peaks at 430nm (a-type) and 470nm (b-type). Thanks to this, blue laser weeding requires lower optical powers to effectively remove unwanted plants.

Absorption Spectrum of Chlorophyll a and b in the Visible Wavelength Range

But it’s not just the absorption that makes blue lasers, and specifically blue diode lasers, well-suited for laser weeding. Blue diode laser systems are much more compact as compared to CO2 systems, which makes blue lasers easy to be installed on different machines and allows many units to be mounted in series. Effectively, blue lasers allow the processing of a larger area at once, which increases the speed of the whole process.

Blue diode lasers are low-voltage, DC systems, which means that they are safer to use in arid environments than CO2 lasers and, at the same time, safer for workers (since CO2 lasers use AC voltage). Blue laser diode systems are light and don’t require water cooling, which positively impacts the vehicles’ fuel consumption. The laser spot size is highly tunable so it can be tailored either for high-precision treatment, or large area operation. Laser diodes also have a higher efficiency than CO2 lasers, so in combination with their long lifetime they are a very cost-effective solution.

Blue Diode Laser Module Used in Weed Control Systems for Organic Laser Weeding

Blue diode laser weeding advantages:

  • Wavelength highly absorbed by plants - no need for exceedingly high optical powers
  • Non-contact method means no physical damage
  • Environmentally friendly
  • Compact size and low weight
  • Cost-effective, requires minimal maintenance

Contact Us for Details

GLE-S-40-B GLE-S-80-B GLE-S-160-B
Center Wavelength 450 nm
Minimum Optical Power 40 W 80 W 160 W
Working Distance 180 mm or 350 mm or 650 mm
Working Area 100 x 100 mm or 200 x 200 mm or 300 x 300 mm
Minimum Spot Size1 2500 um
Operation Speed 2 up to 2000 mm/s
Laser's Electro-to-Optical Efficiency 27 % 24 % 30 %
Maximum Power Consumption 200 W 300 W 600 W

1- values provided for 350mm working distance

2- for angles +/- 10 degrees

50 W Blue Galvo Laser for Automated Weed Control Applications and Organic Laser Weeding

Labeling Food with Opt Lasers' Blue Galvo Laser Engraver Systems

Given the considerable absorption of blue light by plant matter, blue lasers present an efficient option for the purpose of food labeling. Labeling vegetables, fruit, eggs and matured or processed meat with blue lasers is an innovative and practical solution for product identification in the food industry. Blue laser marking offers several advantages for this purpose. Firstly, it allows for precise and high-contrast markings on various surfaces, ensuring that information like origin, quality, and expiration dates is clear and easily readable. Additionally, blue lasers are capable of creating fine, permanent marks without damaging the product's integrity or appearance. This technology also reduces the need for excessive packaging and labeling materials, contributing to sustainability efforts by minimizing waste. Overall, using blue lasers for marking food products not only enhances traceability and safety but also aligns with environmentally conscious practices in the food supply chain.

Kiwi Fruit Labelled with Blue Galvo Laser Engraver Food Labeling System

Read More About Food Labeling with Opt Lasers

Customizable Laser System Features

Our engraving and cutting industrial laser system units can be customized with respect to the following features:

  • Various Optical Power Levels
  • Different Industrial Laser Wavelength Options
  • Customized TTL or Analog Input Voltage Range
  • Increased Maximum Operating Temperature
  • Custom Optics to Produce a Specific Focus Spot Size or Working Distance
  • Special Shapes or Dimensions
  • Private Label Options

Feel free to contact us if you would like to discuss your requirements for a custom laser weed control system.