Scientists Develop Effective Microlasers as Small as a Speck of Dust
Researchers at HSE University–St Petersburg have discovered a way to create effective microlasers with diameters as small as 5 to 8 micrometres. They operate at room temperature, require no cooling, and can be integrated into microchips. The scientists relied on the whispering gallery effect to trap light and used buffer layers to reduce energy leakage and stress. This approach holds promise for integrating lasers into microchips, sensors, and quantum technologies. The study has been published in Technical Physics Letters.
The devices around us are becoming increasingly compact without sacrificing functionality. Smartphones now handle tasks that once required a computer, and small cameras can capture images with quality approaching that of professional equipment. Miniaturisation has also extended to lasers—sources of directed light that are embedded in optical chips, sensors, medical devices, and communication systems.
However, shrinking a laser while preserving its optical properties, efficiency, and reliability remains a significant challenge. Developing a laser measuring 5–8 micrometres—approximately the diameter of a red blood cell—requires complex calculations, and its fabrication demands high precision. The main challenge lies in the design of the laser itself. Unlike conventional light sources, lasers amplify radiation within a resonator—a structure where light is repeatedly reflected and amplified. The more compact the laser, the harder it is to trap the light inside so that it undergoes continuous reflection and amplification without losing energy, which is essential for stable operation.
Another challenge is the presence of defects in the material. Lasers rely on crystals that can amplify light, but microscopic defects often form during their growth, reducing the efficiency of light generation. To minimise these irregularities, scientists carefully select synthesis conditions and simulate the properties of crystals under various scenarios in advance. However, solving one problem often gives rise to others, turning laser development into a continual search for balance.
HSE scientists have developed microlasers with diameters as small as 5 to 8 micrometres that operate at room temperature. The researchers used a crystal structure composed of indium, gallium, nitrogen, and aluminium compounds grown on a silicon substrate. To trap light in a tiny space, the scientists relied on the whispering gallery effect.
Eduard Moiseev
'This phenomenon is well-known in acoustics: in some churches and cathedrals, you can whisper words against one wall, and the sound will be clearly heard on the opposite wall—even though, under normal conditions, the sound would not travel that far. A similar effect enables light to be repeatedly reflected inside the disk-shaped microlaser, minimising energy loss,' explains Eduard Moiseev, Senior Research Fellow at the International Laboratory of Quantum Optoelectronics, HSE University–St Petersburg.
However, even under these conditions, light waves can partially escape into the substrate and be lost. To prevent this, the researchers added a stepped buffer layer, which compensates for mechanical stresses between the silicon and nitride layers and reduces radiation leakage, enabling the laser to operate stably even at such small sizes.
Natalia Kryzhanovskaya
'Our microlasers operate stably at room temperature without the need for cooling systems, making them convenient for real-world applications. In the future, such devices will enable the creation of more compact and energy-efficient optoelectronic technologies,' explains Natalia Kryzhanovskaya, Head of the International Laboratory of Quantum Optoelectronics at HSE University–St Petersburg.
The paper has been prepared as part of a project implemented within the framework of the International Academic Cooperation competition at HSE University.
See also:
HSE Researchers Make Aldehydes Perform Dual Function
Chemists from HSE University have discovered a way to carry out a reductive addition reaction without using an external reducing agent. Instead, the required 'resource' is supplied by the aldehyde itself, one of the reaction participants. This approach helps prevent unwanted side reactions, reduces toxicity, and simplifies the production and synthesis of organic molecules, including those used in the manufacture of medicines. The study has been published in Journal of Catalysis.
HSE Scientists Explain Why Findings in Autism Research Differ
Researchers from the Cognitive Health and Intelligence Centre at HSE University conducted the first-ever systematic review of studies on the specifics of emotion-from-motion perception in autism. The review showed that differences found between autistic and non-autistic individuals are largely associated with the experimental design and the types of tasks given to study participants. The review findings have been published in Research in Autism.
Tremors: Scientists Develop Method for Real-Time Tracking of Hazardous Underground Vibrations
Researchers from HSE MIEM and IPKON RAS have developed a new mathematical monitoring model that can identify the source of hazardous underground vibrations in real time. The technology could help reduce the risk of damage to buildings, roads, and other infrastructure located near quarries and mining sites. The paper has been published in Russian Mining Industry.
HSE Researchers Determine Which Internet Users Are More Likely to Fact-Check
Researchers at HSE University examined the strategies employed by Russian internet users to verify unreliable information and the factors that motivate them to do so. The study found that more than half of users who encounter potentially false information online attempt to verify it by locating the original source. The likelihood of fact-checking is influenced by several factors, including age, place of residence, social status, information literacy skills, and the use of AI. The findings have been published in Monitoring of Public Opinion: Economic and Social Changes.
Tabular Data Anonymisation Solution for Safe Use in AI Systems Developed at HSE University
The AI and Digital Science Institute at the HSE Faculty of Computer Science has developed a tabular data anonymisation service designed to prepare corporate datasets for use in analytics and AI applications. The solution can identify personal data in structured datasets, apply consistent and reproducible anonymisation rules, and generate the artifacts required for quality control, auditing, and subsequent use of data in secure environments.
Population Lifespan Is Governed by Mathematical Laws
Researchers at HSE University and MSU have established a universal law governing the time to extinction of a population in a random environment. Their analysis of the evolution of branching processes—complex probabilistic systems—shows that, regardless of the initial population size, extinction follows strict mathematical laws. The results have been published in the Journal of Applied Probability.
Sociologists: Conservative Consumers Dominate Russian Middle Class
The Russian middle class cannot be regarded as a homogeneous and uniformly stable social group. Similar income levels often mask significant differences in financial strategies, lifestyles, and levels of economic security. This is the conclusion reached by sociologists at HSE University. The study has been published in Voprosy Ekonomiki.
Neurolinguists Assist in Awake Surgery on 11-Year-Old Patient with Epilepsy
Researchers at the HSE Centre for Language and Brain took part in a rare awake neurosurgical procedure performed on an 11-year-old patient with drug-resistant epilepsy. Working alongside surgeons at the Voyno-Yasenetsky Centre of Specialised Medical Care for Children in Solntsevo, they monitored the resection of a portion of the left temporal lobe, where the epileptic focus had been identified.
Scientists Explain How Emotions Shape Attitudes Toward Digital Governance
Today, interactions between citizens and government increasingly take place through digital governance platforms, including digital public services, AI-powered systems, and algorithmic decision-making tools. Until now, however, these technologies have largely been viewed as technical instruments, with their effectiveness assessed primarily in terms of efficiency and user-friendliness. The authors of a new study propose a broader perspective, arguing that digital governance should also be understood as an emotional experience that directly shapes citizens' trust in public institutions.
Neural Network Maps as a Method for Constructing Mathematical Models
Scientists from HSE University–Nizhny Novgorod and the Institute of Physics Belgrade, Serbia, are jointly exploring the application of machine learning techniques and neural networks to the study of nonlinear dynamics. Natalya Stankevich, Leading Research Fellow at the Laboratory of Topological Methods in Dynamics of the Faculty of Informatics, Mathematics, and Computer Science at HSE University–Nizhny Novgorod, spoke to the HSE News Service about this international project.