Metalens fluorometer to assess drinking water in Nepal

Lead Research Organisation: University of York
Department Name: Physics


The country of Nepal has major issues with the quality of its drinking water. Tools to assess drinking water quality are too expensive and not available. We will address this problem by developing a handheld fluorometer to detect tryptophan-like fluorescence as a proxy for bacterial contamination in drinking water. Our novel design is intrinsically simple and can be made at low cost. The core of the instrument is a high numerical aperture metalens that maximises collection efficiency and that can be made by nanoimprint lithography. The metalens will be designed to be strongly chromatic such that the images for different wavelengths are laterally displaced, such that emitter and detector can be placed next to one another. We will develop a translation pathway for prototype instruments to be made in Nepal for use in local communities.

Planned Impact

The main impacts of the project will be societal and economic.

1. Societal impact. Water contamination is a major environmental and health challenge in Nepal, one of the poorest countries on the DAC list. Water contamination from domestic and industrial waste, discharge of untreated sewage and agrochemical pollutants are critical concerns. Water contamination has resulted in severe problems in public health, aquatic and terrestrial life , therefore directly hindering the country to achieve UN Sustainable Development Goals (SDG) 3 (Good health and well- being), SDG 6 (Clean water and sanitation), SDG 14 (Life below water), and SDG 15 (Life on Land). Unfortunately, appropriate water testing laboratory infrastructure and corresponding skilled workforce are not available in Nepal, except potentially in a few labs in the capital city of Kathmandu. As a result, the public are not well-informed, e.g. when to boil or chemically treat water, and diarrhea remains one of the major causes of death and is estimated to be associated with 30,000 deaths annually in Nepal alone. Therefore, the low-cost, portable, rapid, and in-situ tool to assess water contamination we are proposing to develop will have a major impact on the people of Nepal.

2. Economic Impact. Nepal is ranked 109th among 126 countries in the Global Innovation Report 2018. In terms of Human Capital and Research, it is ranked 120th, while in Knowledge and Technology Output Impact it is ranked 124th. There is a strong need for promoting scientific research activities in Nepal to underpin economic activity. Therefore, the research will be undertaken in close collaboration with local partners at Phutung Research Institute (PRI), Kathmandu, Nepal, and the work builds on their expertise in spectroscopy, nanophotonics and instrumentation. The involvement of the local partner along with their local municipality and ensuring support from the local public and political leadership will help the UK project leaders to place technological requirements in a local context, which is the key to ensuring impact of the research and a sustainable future implementation in Nepal. The knowledge transfer from this project, which is critical for the overall development of technology-based research in Nepal, will provide wider academic and industrial benefits, thereby promoting development and welfare of the country in the long run. For example, PRI have already discussed the project with a Nepal-based Angel Investor who may be interested in supporting a spin-out company if this project proves to be successful.


10 25 50
publication icon
Martins A (2020) On Metalenses with Arbitrarily Wide Field of View in ACS Photonics

Description Phutung Research Institute 
Organisation Phutung Research Institute
Country India 
Sector Charity/Non Profit 
PI Contribution We are jointly developing a low-cost fluorometer for testing drinking water in Nepal. My research team are developing the optical system.
Collaborator Contribution We are jointly developing a low-cost fluorometer for testing drinking water in Nepal. The research team at Phutung are developing the electronic system.
Impact We have initial outputs relating to the design of a metalens.
Start Year 2020