Researchers from the University of Rochester and University of California, Santa Barbara, have made a groundbreaking discovery that could change the game for various industries. By engineering a laser device smaller than a penny, they’ve created a tool that can power LiDAR systems in self-driving vehicles to gravitational wave detection – one of the most delicate experiments in existence.

The new chip-scale laser is a marvel of miniaturization, capable of conducting extremely fast and accurate measurements by precisely changing its color across a broad spectrum of light at rates of about 10 quintillion times per second. Unlike traditional silicon photonics, this laser is made with synthetic material lithium niobate, leveraging the Pockels effect to change the refractive index of a material when an electric field is present.

This tiny powerhouse has numerous applications that can already benefit from its designs. For instance, it can drive a LiDAR system on a spinning disc and identify objects at highway speeds and distances. The researchers demonstrated this capability by using their laser to spot toy building blocks forming the letters U and R.

Another significant application is the Pound-Drever-Hall (PDH) laser frequency locking technique, essential for optical clocks that can measure time with extreme precision. A typical setup would require instruments the size of a desktop computer, but the chip-scale laser can integrate all these components into a single tiny chip that can be tuned electrically.

The research was supported in part by the Defense Advanced Research Projects Agency (DARPA) and the National Science Foundation, showcasing the potential of this miniature marvel to revolutionize metrology and beyond.

The portable sensor, called the E-Tongue, has been developed to empower people to detect lead contamination in their own homes. This device was tested through a citizen science project across four Massachusetts towns and has shown promise as a rapid and reliable tool for at-home detection of lead in drinking water.

Ingesting even tiny amounts of lead can harm the human brain and nervous system, especially in young children. Traditional water tests are costly and time-consuming, requiring specialized scientific equipment and long processing times. The E-Tongue device addresses this issue by allowing users to analyze water samples and receive a color-coded reading on their smartphone app.

The researchers behind the E-Tongue worked with 317 residents from four local towns to test its usability and performance. The process was simple: combine a sample of tap water with a premade buffer solution, follow three steps on the smartphone app, and wait for the results.

If lead is detected above the EPA’s maximum allowed level of 10 parts per billion, the researchers verified the results through a certified laboratory using traditional detection methods to ensure accuracy. The E-Tongue device was found to be reliable in detecting lead contamination, empowering communities to take action and protect their health.

The authors acknowledge funding from the National Science Foundation and hope that this tool will soon be a practical option for detecting and mitigating heavy metal contaminants in municipal water sources. By putting knowledge and power directly into people’s hands, the E-Tongue device has the potential to make a significant impact on public health and community safety.

The discovery of a new phenomenon that allows researchers to control solid objects in liquids using ultrasound waves has sent shockwaves throughout the scientific community. The technique, which concentrates solid particles suspended in a liquid by inducing spin through the use of high-frequency sound waves, holds immense promise for biomedical testing and drug development.

At the heart of this innovation is the work of Chuyi Chen, an assistant professor of mechanical and aerospace engineering at North Carolina State University, who explains that the process involves creating ultrasound waves on the surface of a piezoelectric substrate. This causes the fluid inside the droplet to stream in a circle, while the surface tension of the droplet prevents it from spreading out into a flat sheet.

As a result, particles within the droplet are driven by a combination of forces – from the ultrasound waves, the spinning droplet itself, and the fluid moving within the droplet. This movement creates a helical pattern as particles corkscrew through the liquid to come together at a central point.

“This is a novel way of concentrating solid particles in a liquid solution,” Chen notes, “which can be extremely useful.” For instance, by making it easier for sensors to detect relevant materials within cells, this technique could significantly improve biomedical assays.

However, to fully harness this phenomenon and develop technologies that make use of it, researchers need to understand the underlying physics. This is precisely what Chen’s team has achieved in their groundbreaking research.

“This paper lays out in detail the physics responsible for controlling particles inside the droplet,” Chen says. “Now that we understand the forces involved, we can make informed decisions and engineer technologies to concentrate particles in a liquid sample in a controlled way.”

One key aspect of these findings is that researchers can manipulate several parameters – including surface tension, droplet radius, and ultrasound wave amplitude – to influence particle movement within the droplet. This gives them multiple mechanisms for fine-tuning rotation and behavior.

In addition to its potential utility in biomedical research, this new technique also holds promise for exploring fundamental physics questions related to rotating systems. By creating miniaturized tornado-like vortex flows or studying Coriolis-driven transport on a small scale, researchers can gain valuable insights into these phenomena without the need for extensive resources.

The work behind this discovery was supported by grants from the National Institutes of Health and the National Science Foundation. As Chen notes, “This research opens up new avenues for exploring complex physics questions in a compact and relatively inexpensive way.”