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Light: Development

The science and technology of light play an important role in the development and positive evolution of societies, and are essential for maintaining our expanding connectivity to one another. Photonics provides practical and cost-effective solutions to meet global challenges in energy production, sustainable development and healthcare and align well with the United Nations Sustainable Development Goals to end poverty, fight inequality and injustice, and take urgent action to combat climate change and its impacts.

Photonics connects the citizens of the world through the Internet and communications networks, and is a vital enabler for business and education. These networks also support accountability to ensure peace, justice and stronger legal institutions. Optical technologies play a key role in medicine, from simple diagnostics and monitoring to advanced treatment options and research. Remote sensing technologies promote the development of sustainable agriculture to fight hunger and to protect life on land and in rivers, lakes and oceans. Modern lighting provides important opportunities to improve quality of life with efficient and green solutions. And light-based technologies are critical for monitoring and predicting climate change.

In the following we discuss different ways light-sciences and technologies can help address the different Sustainable Development Goals. Note that the importance of these Goals is reflected in the fact that the colours of the 17 Goals in the UN logo are reflected in the rays of the sun in the logo of the International Day of Light itself.

Light and Sustainable Development Goals

The food and agriculture sector is essential to sustainable development. Indeed, ending hunger, ensuring food security, and promoting sustainable agriculture are key objectives of the Sustainable Development Goal targets. In many developing countries, agriculture is also the backbone of the economy, and is a key for long-term and inclusive growth due to its strong multiplier impact on other sectors. Good health and well-being are also fundamental for the development of society.


Light-based technologies can play an important role in improving agriculture and farming through the area of agri-photonics. Lasers and imaging sensors on planes can be used to map soils and crop density, and reflectance data from vegetation can be used to determine very specific information such as the amount of nitrogen present in plants. Lasers and telescopes can be used to monitor evaporation and guide decisions on irrigation, and with appropriate lighting, vegetables and fruits can be grown indoors outside of their normal season, opening up possibilities for year-round crop cultivation, even in inhospitable regions.


Optical technologies play a key role in medicine from simple diagnostics and monitoring, to advanced treatment options, and research. Photonics appears in very simple and widespread devices: clip-on pulse oximeters use the transmission of light from an LED through a finger to measure oxygen saturation and heart rate, and skin thermometers use infrared light detectors to provide a safe and reliable measurement of body temperature. Imaging and surgery have been revolutionized with the use of endoscopy and laparoscopy, and light-based technologies and lasers find important uses in many medical procedures including neurosurgery, dermatology, dentistry, vision correction, heart surgery, and reconstructive procedures. Many light-based therapies have also proven effective for detecting and treating cancer. One example of a light-based technique to treat cancer is photodynamic therapy, where a patient is given a nontoxic photosensitive drug that is absorbed by cancer cells. During surgery, a light beam is positioned at the tumour site, which then activates the drug to become toxic to targeted malignant cells.


Recent years have seen dramatic strides in the field of telemedicine in general, the use of telecommunication and information technologies to provide access to medical services that would often not be consistently available at a distance. The smartphone may well be showing the way towards the democratization of healthcare in developing countries.


Another important issue faced around the world is that worldwide estimates of those who suffer from uncorrected defective eyesight range from the 100s of millions to over a billion adults and children! Far more than just an “inconvenience,” the worldwide lack of eyeglasses to correct vision prohibits people from working and taking care of their families and has a

negative effect on children’s schooling and study.


A number of NGOs and industries are actively working on complementary approaches to solve these problems. One approach uses fluid-filled lenses where a user can self-adjust the eyeglasses, allowing a very convenient way to select the appropriate correction. Another idea uses low cost prefabricated lenses and a compact bending machine to create frames from spring steel; this approach can also encourage the establishment of sustainable businesses producing and selling these glasses in local communities.

In addition to the use of light-based technologies to improve educational infrastructure, light science is an ideal subject to stimulate interest in STEM (science, technology, engineering, mathematics) subjects in a classroom context. Teaching material based on light and optics is widely available and can be inexpensive, and is perfectly suited to inquiry-based, or active learning strategies which encourage students to construct the knowledge from their own observations. This is in contrast to the normal classroom scenario in which the teacher lectures and the students passively absorb as much information as they can, which, by itself, is known to be inadequate in developing correct conceptual understanding of the underlying physics.


One of the major issues of our society is to achieve gender equality. In particular, there is a major concern in the scientific community - regardless of geographical location - to improve the gender-balanced representation of scientists at all levels and promote greater involvement of underrepresented minorities in scientific and engineering careers. According to the UNESCO Science Report: towards 2030, which presents a picture of the trends in global research and development, based on a wealth of qualitative and quantitative data for the past five years, women constitute a minority in the research world. Globally, while women achieve parity at early stages of scientific careers, their participation diminishes with career progression such that women represent only 28.4% of the world’s active researchers! And there are also very significant national and regional differences, with women playing nearly no role at all in science in some countries.


The photonics community have tried to raise awareness of this issue on different levels, comprising initiatives trying to attract more female students to STEM careers, exhibitions to highlight the important role that female scientists have on the development of photonics technologies, and awards for early career scientists on the field of photonics to give visibility to their achievements.


The importance of communications for development is stressed by the UN Broadband Commission for Digital Development, who have recently stated how access to mobile devices (phones, tablets, and e-readers) with broadband internet connectivity can bring quality education to people everywhere, especially in the world’s poorest or most isolated communities. Although it is technology such as fibre to the home (FTTH) that is being emphasized in many developed countries, it is mobile broadband that is perceived as the most practical solution for many developing countries. The International Telecommunications Union (ITU) reports that mobile broadband is the fastest growing technology in history - mobile phone subscriptions now exceed the world’s total population, and active mobile broadband subscriptions exceed 2.1 billion! Significantly, most of this progress has taken place in developing countries, which account for 82% of net additions of new internet users globally in the last five years. The UN Broadband Commission and the ITU are pushing hard to ensure that mobile broadband can fulfil its potential to improve education and development.

Water is essential to human health. Despite impressive gains made over the last decades, billions worldwide still suffer from health problems due to the lack of clean water. Although much progress has been made in the use of conventional treatment processes, there is a continuous need for the development of new and complementary technologies to produce high quality water, especially in developing areas. Photonics technologies can significantly help in this regard by improving both water quality assessment and access to clean sources of water. For instance, low-cost water treatment systems powered by solar panels can decompose organic pollutants in water, and solar-powered well pumping has proven to be a sustainable, low-cost solution to provide drinking and irrigation water in off-grid locations in drought-prone regions. Research is also ongoing into the development of LED-based portable systems for point-of-use purification.

The UN Sustainable Development Goals are an intergovernmental set of goals and targets developed by the United Nations that cover a broad range of sustainable development issues. Light-based technologies can make a fundamental contribution to help accomplish these goals. Communicating these messages is a key component of the International Day of Light. In the following we discuss different ways light-sciences and technologies can help address the different Sustainable Goals.

When one thinks of harnessing light-based technologies for sustainable development, renewable energy through solar power would likely be the first thing that came to mind for most people. After all, many developing countries have abundant solar energy resources (insolation), and the use of solar energy is ideally-suited to providing an off-grid energy supply as a sustainable alternative to the diesel generators which would otherwise be used. There remain many challenges to address, but research is advancing rapidly in the underlying physics and materials science, the development of storage technologies, and in optimising and comparing the technologies of photovoltaics and solar thermal collection.


Closely coupled to the availability of energy is the availability of lighting. With no reliable source of light, many people in developing communities depend on kerosene lamps for light, which have been estimated to lead to the death of over a million people every year. Providing clean, efficient forms of lighting to developing communities is not only important for health reasons - it is also vital for productivity. Families in rural communities rely on work to provide for the most basic needs of their family, but working hours can be limited due to scarce lighting after sunset. The majority of children in developing countries are also expected to work during the day to help provide for their family. With no, or inadequate, light at night, children are deprived of an education. Although longer term solutions will require clear policies on renewable energy at the regional level, many industries and NGOs and other associations are working on the ground to promote the use of portable solar-powered high-brightness LED lanterns in regions where there is little or no other reliable source of light.


Developing countries are at the frontline of human-induced climate change over the next century. According to the to the IPCC Fifth Assessment Report, throughout the 21st century climate change is expected to lead to increases in ill-health in many regions, and especially in developing countries with low income. Rural areas are expected to experience major impacts on water availability and supply, food security, infrastructure, and agricultural incomes, including shifts in the production areas of food and non-food crops around the world.


Light-based technologies are critical for monitoring and predicting the consequences of climate change. They are extensively used to map radiation emitted from the Earth’s surface using radiometers, scanners, and sensors placed in satellites orbiting our planet. These measurements are transmitted to ground stations where the data is converted to images that provide information on ocean currents or global carbon-dioxide distribution.

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