Photonics, or the technology of light, has been applied in many areas such as telecommunications (eg fibre-optic cables), medicine (eg laser surgery) and consumer equipment such as barcode scanners and printers.
It’s now hoped this tech can be further leveraged via precision agriculture to help to keep our food supply safe and sustainable in the long term.
We cannot do without precision agriculture, believes Netherlands-based PhotonDelta, the European hub for the integrated photonics industry.
What is integrated photonics?
Photonics is similar to electronics. However, instead of electrons, it uses photons (light) to transmit information. Photonic technology detects, generates, transports, and processes light. Current applications include solar cells, sensors, and fiber-optic networks. Photonic chips, officially called Photonic Integrated Circuits (PICs), integrate various photonic and often electronic functions into a microchip to make smaller, faster, and more energy-efficient devices. According to PhotonDelta, because they are manufactured like traditional chips (with wafer-scale technology), mass production is also within reach - with price drop as a result.
Via the process, plants or animals receive exactly the treatment they need, determined with great accuracy thanks to a combination of technologies such as robotics and miniaturized biosensors. This allows production to be optimized, leading to more sustainable crops, increased production, and greater food safety: a prerequisite for a future-proof food supply.
Integrated photonics is essential for this, insist the growers at PhotonDelta, which claims photonic chips are lighter, smaller, and therefore more scalable than other solutions. Sensor systems running on integrated photonics ensure that in the agricultural sector and food industry all requirements regarding safety, health and sustainability can be met.
The Netherlands has now built up considerable experience with integrated photonics in precision agriculture, noted Harrij Schmeitz, director of the Fruit Tech Campus in the Netherlands-based grower trainer centre. "There are huge opportunities for photonics in agrifood if we can translate the technology into practical applications that allow the state of the product to be examined on both the outside and the inside."
He cites an example of integrated photonics at fruit grower Fruitmasters in the Netherlands. "They use relatively simple cameras to take 140 pictures in milliseconds of every apple that passes on the sorting belt. This is done in 3D, fully automatically. The system removes the bad apples before they are packed for the customers. That used to be done manually, so that's a big improvement."
Today’s farmers, meanwhile, need record a lot of data, which enables them to plan ahead and learn to give plants exactly the right amount of water, light, and nutrients at the right time. Sensors with photonic chips not only ensure that the data becomes available, but also that the farmer can then use it to better treat his or her crops or animals, noted Schmeitz.
“The first robot that uses camera technology to determine how much to spray the crop has also been introduced. It calculates the needs very quickly when it passes by the crop."
Photonics in the agrifood sector will bring about a change to plant-controlled and tree-controlled cultivation, he elaborated. "With LED lighting you can stimulate crop growth in greenhouses. By using different colours you can accelerate that. In the Westland region, you can see purple greenhouses, because a plant grows better on red and blue light. As a result, you can also use less light, which results in savings for the farmer.”
The application of photonics in agrifood is something on the radar of researchers at the renowned Wageningen University, for instance at the OnePlanet Research Center (a collaboration between WUR, Radboud University, and imec) and at the Eindhoven University of Technology.
OnePlanet Research Center food scientists Lex Oosterveld and Peter Offermans have conduct research into the use of photonics in the food industry and in the cultivation of fruit and vegetables.
"Our technological innovations are aimed at the sustainable production of nutritionally high-quality food and at combating food waste,” explained Oosterveld. “We are therefore developing technology with which the product quality of food can be measured directly, without it having to be analyzed in a laboratory. This allows us to adjust the production process directly." An example is measuring glucose during fermentation processes or in fruit. "The next step is for this to be done fully automatically based on real-time data. In this way, we optimize the production process, and food waste is avoided."
The OnePlanet Research Center is also focusing on the nitrogen issue by developing sensor systems to measure the environmental impact in and around cities, such as in companies and stables. "It is important to accurately map the emission of nitrogen so that you can reduce emissions based on this data,” continued Offermans. "To this end, we have developed a prototype sensor that allows us to measure the amount of nitrate, an indicator of the presence of nitrogen, in water via the light of different wavelengths." This sensor runs on optical chips.
Photonic measuring systems are also relevant for the cultivation of fruit and vegetables, continued Offermans: "An example is ripeness monitoring, which helps the product to be harvested at the optimal moment. This process makes sure the product has an optimal quality at the time of consumption and food loss is prevented. Sensors based on integrated optical circuits fit very well into applications in the agrifood sector, as they are suitable for miniaturization, for combining different sensor types, and for the scalable production of our measurement solutions."
Using infrared light to boost quality control in tomatoes and milk
One start-up that believes photonic technology is key to smart farming is TU Eindhoven spin-off MantiSpectra, which produces sensors that can help determine the health of animals and plants.
CEO Maurangelo Petruzzella and his team have developed a practical application for this purpose. "From the outside of fruits and vegetables, you often can't tell the best time to harvest,” he said. “Farmers can rely on years of experience and on their instincts, but anything can go wrong. If you pick too early, the product may not have reached its maximum flavor; if you pick too late, spoilage can occur. Photonics is a good tool for this."
Petruzzella and colleagues have developed an optical chip that uses infrared light to monitor the ripeness of tomatoes. "We want to develop this chip into a handy device that horticulturalists can use to go into the greenhouse and check individual tomatoes, even before their harvest,” he explained. “Until now, you have to pick a tomato and cut it open to check its freshness. If it is ripe, you have cut into it unnecessarily. The same applies, of course, if it is not yet ripe. Then it's better to leave it on the plant."
The sensor is also suitable for checking the quality of unpasteurized milk and whether cows have health problems. The MantiSpectra chip sensor detects infrared light and can use an algorithm to quickly determine whether the milk is good. Not only is this more accurate and faster, but it also avoids all kinds of additional costs that go into complicated traditional quality checks and wasting good milk, insisted Petruzzella. "The problem is that the quality of milk is usually only measured during its processing,” he explained. "If you are able to measure this directly at the farmers, then you will also know what the health status of the cow is."
Research, production, and applications
While MantiSpectra is a good example of the many applications that integrated photonics has to offer, Oosterveld and Offermans expect that it will take another five years or so before the major photonics breakthrough occurs in the agricultural sector and another ten years or so before it happens in the food industry. Here “it often involves complicated industrial processes that are less easy to adapt”, Oosterveld noted, “which is why the breakthrough there will take a little longer".