The study, published in Optica, explains how properties of luminescent materials and temperature determine the color, intensity, and randomness of light. The findings could help develop advanced light sources, optical sensors, and heat-based photonic systems.
Researchers from the Technion have developed for the first time a complete physical model that explains how the properties of a radiating material – absorption, emission and quantum efficiency – affect the basic properties of the light emitted from the material as a function of temperature. The bottom line: The emitted light changes its color, intensity and randomness depending on the properties of the material and its temperature. The discovery was published in the prestigious journal Optica And it opens up new possibilities for designing advanced light sources, optical sensors, and heat-based photonic systems.
The research was led Intern Tomer Bar Lev and Prof. Carmel Rothschild from the Faculty of Mechanical Engineering and the Russell Berry Institute for Nanotechnology at the TechnionAccording to them, the main phenomenon studied in this work is Photoluminescence Photoluminescence – a process in which a material emits light in response to light shining on it. This phenomenon, in which light particles (photons) are absorbed by and emitted from a material, is at the heart of many technologies, including LED lamps and optical sensors. Technion researchers have shown that the impact of basic physical laws, formulated more than a century ago, is much broader than previously thought.
At the beginning of the last century, physicist Max Planck showed that a body in thermodynamic equilibrium emits radiation depending on the temperature of the substance and its properties. Another German physicist, Gustav Kirchhoff, showed that under the same conditions, The absorption and emission properties of the material must be the same.This work by the Technion researchers goes beyond the particular case of thermal radiation to any radiation and includes the relationship between matter and radiation out of equilibrium. Furthermore, in the pioneering article in Optica they present A general equation that allows one to predict, and especially to shape, the nature of the light emitted from luminous materials.
The new model describes how increasing temperature gradually changes light: from a defined, focused color – like in an LED bulb – to a broad, color-rich radiation like sunlight. In doing so, the model fully explains, and for the first time, how these two phenomena are fundamentally related.
The scientific discovery by the Technion researchers paves the way for controlling the properties of light by changing temperature alone. Potential future developments include advanced optical devices, communications, precise sensing, and applications in the field of optical cooling and heat utilization. According to Prof. Rothschild, "The model we developed provides a broad basis for understanding the properties of light and designing radiation sources characterized by the material properties we desire. This is a new physical infrastructure for next-generation light sources."
The research is supported by the Israel Science Foundation (ISF) and places the Technion at the forefront of global research at the intersection of physics, thermodynamics, and photonics.
For the full article b– Optica click here
Short FAQ
What did the Technion researchers discover?
The researchers developed a physical model that explains how absorption, emission, and quantum efficiency of luminescent materials affect the color, intensity, and randomness of light.
What is photoluminescence?
Photoluminescence is a process in which a material emits light after photons are absorbed by it. The phenomenon is used in, among other things, LED lights and optical sensors.
Why is temperature important?
According to the new model, changing the temperature can change the nature of the emitted light, from a focused color like in an LED bulb to a broader, richer radiation.
What might be the application of the research?
The research may assist in the design of smart light sources, optical sensors, communication systems, photonic devices, and applications in the field of heat utilization and optical cooling.
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