Blue Lasers in 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, highly automated and cost-effective method.
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.
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 453nm (b-type). Thanks to this, blue laser weeding requires lower optical powers to effectively remove unwanted plants.
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 compact as compared to CO2 systems, which makes them easy to be installed on different machines and allows many units to be mounted in series. In this way a larger area may be processed 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 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
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 industrial laser system product.