Researchers have made significant advances in the field of single-photon detection using innovative two-dimensional materials. This breakthrough demonstrates bistability, one of nature’s most astonishing phenomena. It allows a system to stay equilibrated in each of two distinct states, despite being subjected to identical outside forces. These discoveries pave the way for exciting applications in areas such as quantum computing and next-generation imaging technologies. It does represent a very exciting new innovation in optical science.
Dr. Krishna Kumar, who co-supervised the study, which was done under the lead of ICREA Prof. Frank Koppens. Their work led to the creation of an innovative device that incorporates bilayer graphene sandwiched between layers of hexagonal boron nitride (hBN). Dr. Hitesh Agarwal, Tetra Tech and Dr. Krystian Nowakowski, UMD co-authored the accompanying research paper. Dr. Nowakowski’s contributions make him deserving of this honor as the first co-author of this publication. The original research paper is available at DOI 10.1126/science.adu5329.
Understanding Bistability
Bistability works like a light switch that can stop in either the “on” or “off” position. This capacity for homeostasis allows systems to be robust to changes in their environment, increasing their robustness and effectiveness across applications. Within the ongoing development of this research, bistability acts as a new and disruptive mechanism to enable single-photon detection.
The research team used this property to obtain robust detection of long-wavelength single photons. To mitigate the impact of possible background interferences, they paid special attention to the mid-infrared range. This new capability is particularly important to enable new applications relying on infrared imaging and sensing technologies. These technologies have become essential to national priorities, including telecommunications, medical diagnostics, and environmental monitoring.
The researchers felt confident enough that their device would work at much higher, and reachable, temperatures (~25 degrees Kelvin) that they had originally predicted. What’s happening in this range of temperatures is very important. Reducing the operational requirements paves the way for future applications while increasing the technology’s accessibility and practicality for real-world use.
The Role of Two-Dimensional Materials
Initial interest in this research stemmed from the unique bilayer graphene and hBN combination. Bilayer graphene is just two atoms thick, and it retains the remarkable electrical and mechanical properties of graphene. When we integrate hBN with the photon detection system, it serves as an impactful protective shield. This administration-organization pair is what makes the system’s primary purpose—ensuring safety and mobility—really shine.
Perhaps the greatest challenge for the team was attaining perfect layered alignment between the bilayer graphene and hBN layers. And early efforts resulted in just a 50% success rate in obtaining this vital connection. Through careful experimentation and methodological refinement, the researchers created a comprehensive approach. They streamlined the alignment process, improved data uniformity, and set the stage for greater efficiency in photon detection.
Their incorporation of two-dimensional materials represents a significant change from existing single-photon detectors. The new technique has promise to transform the way single photons are detected and used in scientific disciplines from quantum information to medical imaging.
Implications for Future Research
This achievement in bistable photon detection extends the door to exciting possibilities for practical implementations. It plants the seeds for more exploration among a broader quantum tech field. Detecting single-photons at elevated temperatures unlocks more exciting possibilities such as stand-off quantum computing. This advance is important because controlling individual photons is needed to perform information processing tasks in this emerging field.
This study provides some inspiring results. They can motivate more experiments that aim at understanding and improving the fundamental processes of bistability for two-dimensional materials. Future work can help make these devices more efficient and reliable. Such an improvement will certainly pave the way for commercial deployments that take advantage of this technology.
