Founding partners and members Visiting address

LeidenUniversity, Gorlaeus Laboratories, BiosciencePark, Einsteinweg 55, 2333 CC Leiden, The Netherlands

Postal address

P.O. Box 9502, 2300 RA Leiden, The Netherlands

Contact person

Dr. Eduard van Wijk (


All living organisms spontaneously emit photons albeit in varying levels of intensity. These photons also indicated as biophotons or ultra-weak photon emission (UPE) are emitted in the visible light range (300 – 750nm) as a result of the energy released by radical oxygen species falling back to less energetic states. Radical oxygen species (ROS) are produced in every cell that is capable of oxidative respiration. For several decades it is possible to measure these ultra-weak photons using photon multiplier tubes and Charge Coupled Device systems (CCD).

Diagnostic properties have been discovered in relation to human ultra-weak photon emission (UPE). Recently, a systematic review on the use of ultra-weak photon emission as a non-invasive health assessment appeared. Since photon emission is measured over a period of time, dynamical information about the body is obtained. Therefore, photon emission seems very suitable to study the dynamics of health and disease.

Recent developments

Although most of the early UPE measurements were mostly focused on determining the intensity of the signal, a new research area has recently opened up in which novel methods of analyzing are developed. For instance, fractal properties of the signal have been related to subtypes of pre-diabetes. Squeezed state parameters, applying calculations from the quantum optics fields, have revealed differences between people with a longstanding practice of meditation and people just recently practicing meditation. Thus, signal properties can reveal information about the health or sub-health state of a person.

A very recent development in The Centre is the attempt to integrate human ultra-weak photon emission data with other types of data obtained from the same individuals. Since UPE results from oxidation reactions in the body, an obvious area to look for relationships is blood and urine metabolites. Biochemical changes in lipid peroxidation, oxidative stress, energy metabolism and other pathways can be measured for developing a deeper understanding of the molecular mechanisms behind photon emission. This also allows the building of an integrated systems view of processes in the body that are related to health maintenance from the molecular level up towards the organization of dynamic photon emission patterns.

The current research effort

The current research effort of the Center of Photonics in Living Systems is to develop novel non-invasive diagnostic tools based on ultra-weak photon emission. These tools consist of the technology to measure the photons, the development of novel photon count statistics and parameters, tools to integrate photon emission data with other types of data and conducting studies in healthy and sub-healthy humans.

Since the Centre is embedded in a Systems Biology environment (Leiden University, Netherlands Metabolomics Centre, TNO) there is a high integration of UPE data with other types of measurements such as metabolomics. This will be key to understand the complexity of the human body.

The future lies in the further development of an integrated UPE and metabolomics platform for a personalized monitoring of changes of the system towards health or disease.

Educational activities

New book: Light in Shaping Life. Biophotons in Biology and Medicine (2014) by Roeloed van Wijk.
Education about the field of ultra-weak photon emission in biology and medicine has a high priority. The Centre offers the possibility for training in biophoton research, i.e., the use of photomultiplier and CCD equipment as well as the application of strategies for data analysis. Several students have followed the training and are currently applying these techniques in their PhD research. For general information, the textbook “Light in Shaping Life - Biophotons in Biology and Medicine” (2014) can be used. It encompasses the history of biophoton research, insight into how biophotons are generated, and into their involvement with life. Also included, is an overview of the potential benefits of such research to a better understanding of health and medicine. Training in specialized topics is based on recent scientific articles on that topic.