Sustainability is one of the greatest issues of our time. From multinational businesses to individuals, we’re seeing more and more action being taken to reduce our collective impact on the environment. 

New technologies are one of the best tools we have towards achieving this goal. According to the United Nations Environment Programme, technological developments are “key to addressing environmental degradation, climate change, food scarcity, waste management, and other pressing global challenges”.  

Among these new technologies are short-wave infrared (SWIR) imagers and sensors powered by quantum dots. These nanoscale semiconductor materials facilitate high-performance SWIR imaging at a fraction of the cost of incumbent solutions, making this revolutionary technology available to everyone involved in the fight against climate change. 

Take for example the growing problem of plastic pollution in our oceans. Millions of tonnes of plastic are dumped into the ocean each year, causing irreparable harm to wildlife through entanglement or ingestion. What’s more, these pollutants slowly break down into microplastics, which are increasingly being detected in fish caught for human consumption as well as other food items. 

Methods for identifying and removing plastics from the ocean are often limited by time and logistics. Such retrievals require extensive efforts to identify the pollutants, never mind the time and financial costs of removing them.  

However, again, SWIR cameras can simplify this process. The IR absorption characteristics of plastic materials mean they are easily detectable through SWIR imaging. Because SWIR wavelengths are better able to penetrate water than long- or mid-wave infrared light, drones equipped with these cameras are better able to detect marine plastics – enabling teams to quickly find them and begin the extraction process. 

This same principle can be applied to soil quality monitoring. SWIR imager-equipped drones or satellites are able to detect pollutants in the ground or monitor the health of plants. This process can even be used for food quality inspection, helping to address another environmental challenge: food waste. 

Approximately a third of all food produced for human consumption is wasted each year. This is equivalent to around 1.3 billion tonnes, and is valued at $1 trillion, or enough to feed 3 billion people. 

This level of waste has disastrous consequences for the environment. Food waste accounts for around 4.4 gigatonnes of greenhouse gas emissions each year – which, if it were a country, would position food waste as the third largest greenhouse gas emitter in the world. 

Traditional food sorting systems rely on the visible spectrum to analyse produce by shape and by colour. This means that while they can detect surface detects and contaminants in terms of products that should not be there. However, less visible defects, such as bruised or rotting produce, or foreign objects embedded in the food, cannot be detected by colour sorting machines. This means it is more likely to pass through sorting. With the damage contributing to faster spoiling, the result is almost certainly higher food waste rates. 

This is where nonvisible scanning can make a significant difference. Water’s absorption coefficient peaks at 1,440nm, which is in the SWIR range. This means SWIR wavelengths are often absorbed by water, leading to water showing up as a darker area on a SWIR imager. As a result, SWIR imagers can detect bruises in food before they have even fully formed, because bruises accumulate moisture. Alternatively, the absence of moisture in a food item could indicate the presence of a foreign object. 

More advanced hyperspectral imaging systems can also detect bacteria, insect infestations, and even firmness or ripeness in a non-destructive way, helping to further to reduce food waste. 

Other uses include helping emergency response crews tackle forest fires and other similar disasters. SWIR cameras are uniquely capable of imaging through atmospheric smoke and pollution far better than visible light cameras. This is because SWIR photons are better able to penetrate atmospheric haze without being scattered by pollutants in the air, unlike visible light photons. These airborne particles often completely block light in the visible spectrum, but SWIR light can pass through virtually unimpeded.  

As a result, using SWIR imagers can enable satellites to monitor the first moments following ignition with high levels of detail, easily tracking location, speed, and direction of expansion. Using this information, firefighters on the ground can take more effective action to limit the fire’s spread, potentially saving lives and land. 

These are just a snapshot of the ways that quantum dot-equipped SWIR sensors can help tackle some of the biggest environmental issues we face. Facilitating high-performance and affordable SWIR imaging, quantum dots are the key to a wide range of new technologies that can make a real difference for sustainability. This technology is one of the most exciting developments of recent years, and as it becomes more widespread, it could be one of our greatest tools to help protect the planet. 

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