Which Type of Laser Can Be Used for Laser Weeding?

Laser Weeding

Laser weeding is an innovative, chemical-free approach to agricultural weed control that uses high-energy light beams to destroy unwanted plants. Several laser types are currently used in this application, each with distinct advantages depending on the specific weeding scenario.

Laser weeding systems primarily use carbon dioxide (CO₂), diode, and fiber lasers. The specific type of laser is chosen based on factors such as efficiency, portability, and how their wavelength interacts with plant tissue.

Types of Lasers Used for Weeding

CO₂ Lasers:

These are the most common type used in early commercial systems, such as those by Carbon Robotics. They operate in the far-infrared spectrum (around 10,600 nm) and rely on heating the high water content of plant cells to create thermal damage, essentially boiling the plant tissue.

• Pros: Highly effective at damaging the plant surface.

• Cons: Low energy efficiency, large size, heavy, and require water cooling systems, making the overall machine bulky and increasing fire risk in dry conditions. The infrared beam is absorbed by water droplets on leaves, which can reduce efficacy in wet conditions.

Diode Lasers and Blue Lasers: 

Diode lasers typically operate in the near-infrared (around 940 nm or 980 nm) or visible blue light spectrum (around 450 nm). Blue lasers are gaining prominence as a state-of-the-art solution.

• Pros: More compact, lightweight, highly energy-efficient, and run on lower voltage, which increases safety in the field. Blue light is strongly absorbed by chlorophyll and transmits very well through water, making it highly effective even on wet leaves or in flooded fields.

• Cons: May require more energy per weed compared to a CO₂ laser in some specific scenarios, but their overall system efficiency is higher.

  

Dongguan Blueuniverse Laser Co., Ltd manufactured blue diode lasers from 1W to 500W, we also can offer professional OEM&ODM service for weeding control lasers.

• 60W Optical Power 450nm 60W Blue Diode Laser Module for CNC Laser Cutting Machine from China manufacturer - BU-LASER

• 80W Optical Power 435nm 80W Blue Laser Diode Module for CNC Cutter Engraver Machine from China manufacturer - BU-LASER

• High Power 435nm 80W Blue Laser Module with Air Cooler for Laser Weeding from China manufacturer - BU-LASER

Fiber Lasers: 

These are solid-state lasers that use a doped glass fiber as the active medium and typically emit in the visible to near-infrared spectrum. Thulium-doped fiber lasers operating at around 2 µm are particularly effective because the radiation penetrates deeper into the plant tissue to heat the internal water, rather than just the surface.

• Pros: Offer very high beam quality and are robust for field use with minimal maintenance.

• Cons: Can be more expensive than CO₂ systems on a price-per-watt basis.

In essence, while different laser types are used, the trend in robotic weeding systems is moving towards more compact, energy-efficient blue diode and fiber lasers due to their practical advantages in a field environment.

BU-LASER provides Diode laser modules with multiple specification choices(output power, beam divergence, beam size, working distance, and dimension) better meet customers’ needs of accurate laser positioning/locating/orientating. To know more, please contact us at song@bu-laser.com.