Photonic snakes, a new instrument for revealing the secrets of light

Photonic snakes, a new instrument for revealing the secrets of light

Photonic snakes, a new instrument for revealing the secrets of light

Researcher Salim B. Ivars, a doctoral student at the UPC’s Department of Physics, has collaborated with researchers from the Institute of Photonic Sciences and the Universitat Politècnica de València in the discovery of the so-called photonic snake states, a novel instrument that can greatly assist in unravelling the mysteries of light. The results of this research, led by the UPV, have been published in the scientific journal Nature Photonics.

Sep 04, 2023

With its myriad colours, light is one of nature’s wonders. Truly understanding what we see requires us to know the colour of the light shaping our perception of the world. We accomplish this through optical rulers known as frequency combs, the application of which won the Nobel Prize in Physics in 2005.

These optical rulers are used to measure not only colours but also time, distance and other critical quantities. As such, they play a pivotal role in scientific and technological applications, enabling us to explore and uncover the profound mysteries of light. Now a recent study led by the Universitat Politècnica de València (UPV) has achieved a breakthrough. The study features researcher Salim B. Ivars, a student on the doctoral degree in Computational and Applied Physics affiliated with the Department of Physics of the Universitat Politècnica de Catalunya - BarcelonaTech (UPC), and Lluís Torner, director of the UPC’s Institute of Photonic Sciences (ICFO). Researcher Yaroslav V. Kartashov, from the Institute for Spectroscopy of the Russian Academy of Sciences (Moscow), has also participated.

Published in the scientific research journal Nature Photonics, the work has unveiled a new tool called photonic snake states for further deciphering the secrets of light. It opens up unprecedented possibilities in frequency comb formation: it postulates the existence of two-dimensional optical rulers, which are more complex than the one-dimensional ones used so far and provide unmatched versatility in a wide range of applications. The study has captivated the international scientific community.

Applications in communications, spectroscopy and computing
Frequency combs have a huge number of applications, especially in the field of communications. The authors of the study explain that these combs enable the efficient transmission of large amounts of information via optical fibres. By relying on well-defined frequencies, multiple light signals can be sent simultaneously and separated easily when they are received.

Frequency combs also play an essential role in spectroscopy. They allow optical spectra to be obtained with unparalleled accuracy and resolution, facilitating the identification of different substances. This is particularly useful in chemistry, biology and medicine, where molecule detection and material characterisation are critical.

In metrology, the science of measurement, these structures serve as a reference to define standards due to their ability to generate stable and known frequencies. They enable very precise measurements of fundamental quantities, such as time and length, which are essential in most scientific fields.

Finally, frequency combs have shown promising potential in quantum computing, where light particles or photons play a fundamental role. In particular, frequency combs can generate single photons with specific properties, which is essential for advancing these technologies.

The future of optical rulers
The development of these optical rulers faces a fundamental challenge: the instabilities that occur when constructing them. These instabilities hinder the generation of versatile light forms. As professor Pedro Fernández de Córdova, a researcher at the UPV’s IUMPA and co-author of this work, points out, “it should be noted that our team has obtained, from a theoretical perspective, the conditions for the light structure to be stable, finding zigzag-shaped configurations that we have called photonic snakes. The stability of these light states is a crucial aspect for future applications.”

The study has also demonstrated the feasibility of creating a two-dimensional arrangement of synchronised and individually accessible optical rulers. This finding allows for a wide range of rulers to be generated in a single device and controlled by a single laser light source. In fact, as professor Carles Milián, who lead the research, explains: “The potential impact of this breakthrough is extraordinary, as it could enable the development of reconfigurable, broadband monolithic multicomb devices. These devices would provide different frequency combs on demand and in real time, significantly expanding existing applications.”

This study is based on thorough and comprehensive theoretical models, which have considered all known effects that could surface in future two-dimensional frequency comb formation experiments, using robust theoretical and numerical tools. In fact, as professor J. Alberto Conejero, director of the UPV’s Department of Applied Mathematics and co-author of this work, points out, “this research has built a very precise model that includes all the phenomena that can influence the formation of these structures. It will work as a guide for future experiments, with the consequent economic impact of knowing in advance the experimental parameters with which stable light snakes can be generated.”

According to ICFO director Lluís Torner, “this important discovery is remarkable for being unexpected and surprising, and has been possible thanks to the intuition and leadership of professor Milián.”

The UPV, UPC and ICFO team state that this finding will further stimulate research in this field and lead to revolutionary new applications and technologies. “Thanks to these advances, we are one step closer to unravelling the mysteries of light and harnessing its full potential for the benefit of our society,” they conclude.