Outreach

Light, present in all fields and facets of life

• On the occasion of the International Day of Light, INAOE researchers reflect on the relevance of its study.
• Light is present in the development of important applications in medicine, industry, communications and computing.
• Quantum mechanics will drive the next technological revolution.

Santa María Tonantzintla, Puebla, May 17, 2024. This May 16, the International Day of Light was celebrated to raise awareness in society about the relevance of the study of light and its contributions in practically all fields and facets of life.

Optics, a science that studies light, is one of the main scientific areas of the National Institute of Astrophysics, Optics and Electronics (INAOE), a Public Center coordinated by the National Council of Humanities, Sciences and Technologies (Conahcyt).

On the occasion of the commemoration of the International Day of Light, researchers from the Optics Department talk about light, its applications and some of the most important contributions of the Institute in this field.

Light, explains Dr. Rubén Ramos García, can behave as a wave or as a particle, depending on the nature of the experiment: “The acceptance of the wave nature of light was a gradual process that involved the accumulation of experimental and theoretical evidence. From the early ideas of Huygens to the crucial experiments of Young and the mathematical formulations of Fresnel and Maxwell, the understanding of light as a wave was fundamental to the development of modern physics.”

He adds that ”Newton's corpuscular theory dominated scientific thought for most of the 18th century, thanks to Newton's prestige and the apparent ability of his theory to explain many known optical phenomena. However, he could not explain Young's experiments, giving a temporary triumph to the wave theory. In 1905 Einstein proposed that light is composed of discrete energy quanta, called photons. This idea was based on Max Planck's work on blackbody radiation, where Planck introduced energy quantization. Finally, De Broglie proposed in 1924 that not only light, but all particles such as electrons, also have wave properties. This idea was revolutionary and established the basis of quantum mechanics.”

Dr. Francisco Soto Eguibar asserts that the study of light is relevant because it helps us understand the universe, drives the development of important technologies, improves medicine and biology, promotes innovation in imaging technology, and enriches our culture and artistic expression.

Dr. Fermín Granados Agustín, coordinator of Optics, comments that the manipulation of light has allowed us to develop current technology in communications, instruments for the diagnosis and treatment of diseases and the manufacture of lenses and mirrors for microscopes and telescopes that help us to understand nature better.

In today's world, he adds, there is no activity that is not related to light: “Light is used in the manufacture of high-precision mechanical parts such as seals in hydrocarbon pipelines. It is also used in the manufacture of microcircuits thanks to lithographic systems, which are nothing more than projectors on a mask where the circuit designs is placed. The trend is to make them smaller and this implies that the wavelength used for these sources is also smaller. In computing there is the trend towards quantum computing, which will allow photons and light to be transmitted instead of electrons. This is under development in the area of Quantum Optics. There will be a revolution,” he assures.

He reports that the study of Optics began at INAOE due to the need for new large instruments, such as the telescope of the Guillermo Haro Astrophysical Observatory in Cananea: “However, over time the area began to grow and develop various topics. In the area of Optics we have eight lines of research that range from biophotonics and photonics to instrumentation, physical optics, statistical optics, quantum optics and image processing.”

For Dr. Baldemar Ibarra Escamilla, the application of light in space technology stands out. “We are talking about LIDAR (Laser Imaging Detection and Ranging). Some years ago, sending and receiving information was done through radar and today it is done with laser light. LIDAR is a modern detection system that allows us to know what is in the sky and also what is on Earth.”

Dr. Baldemar Ibarra works with laser light and optical fibers which have many applications. “Laser light is generated through optical fiber. In particular I work on fiber optic lasers to generate light in the 1550 nanometer wavelength region, which were originally used for telecommunications but now have other applications, and also to generate light in the 2000 nanometer wavelength region or two microns. We cannot see infrared light, only visible light."

Likewise, he added that, "in telecommunications, a wavelength of 1550 nanometers can be transmitted over longer distances because this wavelength has less losses within the fiber, since the light dims within it. This wavelength allows amplifiers to be placed at greater distances. The other wavelength with which I work is two microns, which we cannot see with the naked eye either. In medicine or biology there are many applications. In particular, I began to study this in 2012 due to a kidney stone problem. In these operations they see, detect and destroy the stones with this light.”

Dr. Rubén Ramos, leader of the INAOE Biophotonics group, considers that light is central in medicine: “with light you can diagnose and treat diseases in a non-invasive way. In hospitals, light is used to make cuts, correct visual defects, break up clots, monitor blood flow in the skin, treat cancer and many other applications.”

INAOE Biophotonics group develops various projects to aplly light in medicine. One of them seeks to inject medications using laser-generated jets: “In a cavity that contains the medication to be injected, we generate a bubble that expands at high speed, generating a jet thinner than an insulin needle and that travels more than 300 kilometers per hour and penetrating the skin without pain. We are currently developing a prototype that we will seek to commercialize.”

In another project, microparticles and organelles, in the case cells, are manipulated using optical tweezers: “By monitoring how the organelles move inside the cells we can determine the viscosity of the intracellular medium, which allows us to determine the state of health of the cell without physical contact.”

He reports that Dr. Teresita Spezzia is working on treatments to kill bacteria, fungi and cancer cells: “Fungi and bacteria are resistant to drugs due to excessive use of them. With photodynamic therapy they can be killed regardless of the degree of resistance to the drug. The same technique can be used to kill cancer cells.”

They also use light to see through the skin. “Skin is a highly scattering medium, making it difficult to see through it. It's like if you want to see through frosted glass, we can see that there is something behind but we can't see details. With single pixel imaging we can get rid of those effects and see through the skin clearly.”

Dr. Julio César Ramírez San Juan develops a project to illuminate the skin with coherent light and see how blood flows through the veins. “This is important in cancer treatment since cancerous tumors require many nutrients provided through the blood. The cancerous tumor releases growth factors creating new blood vessels. With visible radiation, blood vessels can coagulate and with the technique known as laser speckle imaging, the degree of coagulation can be determined and, therefore, leading to tumor shrinkage.”

Finally, in collaboration with Dr. Svetlana Mansurova, they are working on a plasmonic biosensor for the detection of the SARS-CoV-2 virus.

For his part, Dr. Francisco Soto Eguibar asserts that light plays a fundamental role in a wide variety of fields, from science and technology to art and medicine. “Light is fundamental in physics, since it is the basis of optics, the study of its behavior and its interactions with matter. The understanding of light has led to the development of theories such as quantum mechanics, electromagnetic theory, and the theory of special relativity, among others”.

Light-based technology, he notes, has had a significant impact on a wide range of fields, from communications and medicine to electronics and entertainment, improving efficiency, precision and quality of life in modern society.

Specifically, in scientific research, light is used to study natural phenomena, such as the behavior of materials at the molecular level, the structure of the universe and bioluminescence in living organisms, among many others.

Light has a significant influence on a wide range of fields, from the exploration of the universe to the design of advanced technologies and artistic expression. Its versatility and ability to reveal information make light an invaluable resource in modern society.

To conclude, Dr. Soto mentions some of the contributions of the INAOE in this field: research in various areas of astronomy, including stellar astrophysics, the formation and evolution of galaxies, high-energy astrophysics and the detection of extrasolar planets; the development of advanced optical technologies including light detection systems, design and manufacturing of optical components, and high-resolution imaging systems with applications in various fields; international collaborations, the training of human resources and scientific dissemination.

Finally, Dr. Iran Ramos Prieto talks about light from the perspective of quantum optics: “Although it is commonly accepted that light exhibits a dual nature, manifesting itself as a wave and a particle, this description may be insufficient and even contradictory. From my point of view, our limited understanding leads us to conceptualize it in this way, but in reality, its nature goes beyond these conventional categories”.

He indicates that light, “understood as photons, is fundamental to the emerging field of quantum communications. The ability to transmit information securely using the principles of quantum mechanics, such as entanglement, superposition, promises to revolutionize communications security.”

In quantum computing, qubits represent a means of carrying out quantum operations, which could potentially lead to significant advances in computing power and complex problem solving.

“Quantum optics have been the driving force behind progress in highly sensitive sensors. Devices based on photon detection enable extremely precise measurements in fields such as metrology and the detection of small fluctuations in electromagnetic, gravitational or magnetic fields.”

Some areas revolutionized with the use of light-based technology are quantum communications, quantum computing, quantum cryptography, quantum metrology and quantum imaging. Furthermore, “technology based on quantum light has revolutionized fields such as quantum detection of physical phenomena, quantum teleportation, quantum spectroscopy and research into the foundations of quantum physics.”

Dr. Irán Ramos emphasizes that the study of quantum light “is crucial because it provides us with a deeper understanding of the fundamental nature of light and reality itself. Exploring the quantum phenomena associated with light challenges us to rethink our traditional conceptions of physics and provides us with innovative perspectives on the nature of the universe and the way we interact with it. It also allows us to understand and harness valuable phenomena in quantum physics to revolutionize technologies in communications, computing, sensing, imaging, and many other areas.”

He highlights the contributions of INAOE in the field of quantum optics: “the establishment of a solid theoretical framework that facilitates the understanding of the various forms of interaction between radiation and matter, as well as the exploration of analogies between classical domains. and quantum.”

More recently, an innovative application of tools from quantum mechanics and quantum optics has been observed to resolve and analyze the propagation of light beams.

In conclusion, “from first principles, the study of the interaction phenomena between radiation and matter continues within a conceptual framework defined by optics and quantum mechanics.”