Blue Lasers for Automated Organic Laser Weeding
Blue Laser Precision for Sustainable Agriculture
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.
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.
Our Mission
We believe that our customers’ success is our success. That’s why we don’t develop AI systems – we specialize in building reliable, high-performance laser hardware. Our focus has always been on quality, precision, and long-term trust. With extensive in-field experience and partnerships with over 7 integrators, we deliver real, tested solutions that work in agriculture – not just in theory.
At Opt Lasers, we don't just sell components — we co-create your weeding system. Our patented technology, proven integration support, and direct collaboration with manufacturers make us more than a supplier. We're your development partner.
Whether you're building a robotic weeder, autonomous platform, or next-gen agri-tech solution — we'll help you get it field-ready.
Field-Proven Performance in Real Agricultural Conditions
Our blue diode laser systems are not just lab-tested — they are actively tested and deployed in the field by over 7 integration partners across Europe. From arid environments to high-density vegetable farms, our technology has consistently delivered precise, efficient and safe weed control.
Each partner has helped validate and refine our systems through real-world usage. We continuously collaborate on developing new generations of laser modules, with fully customizable configurations tailored to your application — whether that means boosting speed, improving weed kill rate, or reducing maintenance overhead.
Our engineering team works directly with OEMs and automation companies, providing guidance not only on the laser system, but also on optimizing the machine itself — from cooling layout to scanning angles and control signals. We support our partners through every step of product development, from proof of concept to commercial launch.
Laser Technologies Compared – Blue vs IR vs CO₂
Table below shows comparison of different wavelengths used for laser weeding. Values scaled to 320W optical output power, liquid cooling applied and original values are taken from existing products specification:
| Feature | 450 nm Blue (Tomorrow’s System) | 2000 nm IR | 10600 nm CO₂ |
|---|---|---|---|
| Efficiency (Wall Plug AC) | 19% | 12.3% | 11.2% |
| Optical Output Power | 320 W | 320 W | 320 W |
| Total System Power Draw (incl. cooling) |
1700 W | 2600 W | 2870 W |
| Weight (Laser + Electronics) | 14 kg | 48 kg | 18 kg |
| Weight with Cooling & Enclosure | 44 kg | 88 kg | 118 kg |
| CO₂ Emissions per 100h Use (700 g CO₂/kWh) |
119 kg | 182 kg | 200 kg |
| % of Pass-Through for 1 mm Water Layer | 99.99% | 36.79% | 0% |
| Laser Source Volume | 11 dm³ | 270 dm³ | 155 dm³ |
| Price per Watt | 37.5 EUR/W | 100 EUR/W | 20–50 EUR/W |
With its unmatched transmission through water, high efficiency, low weight and lower environmental impact, blue laser technology stands out as the future of safe and scalable laser weeding.
Electrical Efficiency Comparison and Explanation
Laser system efficiency is critical for minimizing energy consumption, reducing operational costs and ensuring reliable performance in field applications. Here's how the electrical efficiency compares between 2000 nm IR, CO₂ and 450 nm Blue laser systems:
2000 nm IR Lasers: A 200W IR laser typically draws 1200W of electrical power, yielding a laser-only efficiency of 17%. However, it also requires a water chiller rated for 1700W of heat dissipation, consuming 600W of input. Adjusting for cooling load (424W), the final system efficiency becomes 12.3%.
CO₂ Lasers: A 130W CO₂ laser tube with its power supply draws 860W. The same 1700W chiller contributes another 303W (based on proportional load). The resulting total efficiency drops to 11.2%.
450 nm Blue Lasers (Tomorrow’s System): A 120W blue laser draws 356W, uses 95% efficient drivers and 62W of air cooling. This results in 120 / (356 / 0.95 + 62) ≈ 26.7%. Using a 48V power supply with 91% efficiency, the overall system efficiency becomes 24.3%. For 320W configurations with liquid cooling, efficiency may reduce to around 19%, with total system power reaching 1800W.
Tomorrow’s System achieves these high values through in-house design of both laser sources and dedicated drivers. In contrast, many off-the-shelf drivers operate at only 70–90% efficiency, which significantly lowers the performance of the entire laser system.
Water Absorption and Irradiation Dose – Key Factors in Laser Weeding
Water absorption significantly impacts laser light transmission and the actual energy dose received by weeds. Laser systems operating at different wavelengths show vastly different behaviors when interacting with water droplets on plant surfaces.
Transmission through water: For a thin 0.1 mm layer of water, blue laser light transmits with almost no loss (99.99%), while 2000 nm IR light drops to 90.48% and CO₂ laser light drops to nearly zero (0.004%). Even a small amount of moisture can completely block CO₂ and partially suppress 2000 nm laser irradiation.
With a 1 mm water layer, the transmission coefficients are:
- Blue laser: 99.99%
- 2000 nm laser: 36.79%
- CO₂ laser: 0%
Impact on irradiation dose: In short treatment windows (50–100 ms), a water droplet (5×5×1 mm³) absorbs the entire CO₂ dose and about 63% of the 2000 nm laser dose. For the IR laser, this absorbed energy raises the droplet's temperature from 20°C to boiling using just 8.4 W, but only 8–10% of it will evaporate. This limits how much energy actually reaches the weed, reducing effectiveness.
Flooded or irrigated fields: In deep water layers such as rice paddies (10 cm), blue lasers still transmit over 99% of energy to the target, while 2000 nm and CO₂ lasers deliver virtually zero.
This analysis shows that even light rain or irrigation significantly affects the performance of IR and CO₂ lasers, while blue laser systems remain highly effective in wet environments.
Weight, Dimensions and Their Influence on Integration
In mobile or field-based laser systems, weight and physical dimensions significantly impact integration, mobility, and power consumption. Blue lasers offer clear advantages in both areas:
The total weight of a 320W blue laser system, including cooling, is estimated at only 14 kg. In contrast, a 200W 2000 nm laser system weighs around 61 kg with its cooling aggregate, and a typical CO₂ laser setup weighs approximately 48 kg. This means that two blue laser modules combined still weigh less than a single 2000 nm or CO₂ laser system.
Dimension-wise, blue lasers are extremely compact. A 320W blue laser module measures no more than 100×300×300 mm — under 10 dm³. By comparison, a 2000 nm laser system occupies over 169 dm³ and a CO₂ laser system reaches 92–97 dm³. Additionally, CO₂ lasers are often built from fragile glass tubes, measuring up to 165 cm in length, making them difficult to mount or protect in mobile settings.
In conclusion, blue lasers are more than 12 times smaller than 2000 nm IR lasers and over 7 times smaller than CO₂ laser systems. These compact dimensions enable mounting on lightweight agricultural vehicles or robotic arms, dramatically increasing flexibility in field deployment.
Advancing Precision Weed Control with Blue Laser Technology
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.
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 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
Opt Lasers Blue Laser Systems for Laser Weeding
| GLE-S-30-B | GLE-S-60-B | GLE-S-120-B | Custom Modules |
|
| Center Wavelength | 450 nm | 450 nm | ||
| Minimum Optical Power | 30 W | 60 W | 120 W | 60–500 W |
| Working Distance | 180 / 350 / 650 mm | Selectable per design (e.g. 180 mm for short-range, 650 mm for high-clearance) |
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| Working Area | 100×100 / 200×200 / 300×300 mm | Custom scan field based on optics & galvo |
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| Minimum Spot Size1 | 2500 µm | Adjustable optics (precision vs coverage) |
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| Operation Speed2 | up to 2000 mm/s | Configurable up to 2000 mm/s |
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| Electro-Optical Efficiency | 27% | 24% | 24% | TBD |
| Max Power Consumption | 200 W | 300 W | 600 W | TBD |
1 – values provided for 350 mm working distance
2 – for scanning angles ±10°
