Physicists at the University of Colorado Boulder have demonstrated a new type of vacuum ultraviolet laser that is 100 to 1,000 times more efficient than existing technologies. <\/p>\n
The device could allow scientists to observe processes currently beyond the reach of powerful microscopes and help advance ultra-precise nuclear clocks.<\/p>\n
The research team says the laser can generate bright light in the vacuum ultraviolet region of the electromagnetic spectrum, an area scientists have struggled to access with practical systems.<\/p>\n
Such lasers could allow researchers to track chemical reactions in real time, detect microscopic defects in nanoelectronics, and study materials with much higher resolution than before.<\/p>\n
The device is compact enough to sit on a desk, a major shift from existing systems that often require large laboratory setups.<\/p>\n
Breaking the VUV barrier<\/p>\n
The work is led by physicists Henry Kapteyn and Margaret Murnane of JILA, a joint institute of the University of Colorado Boulder and the National Institute of Standards and Technology.<\/p>\n
\u201cScientists have been working toward vacuum ultraviolet lasers for decades,\u201d Kapteyn said. \u201cWe think we might have finally found a great route that can be scaled in power, and that is compact in size.\u201d<\/p>\n
Visible light wavelengths range from about 380 to 750 nanometers. Vacuum ultraviolet wavelengths are much shorter, roughly 100 to 200 nanometers, allowing scientists to see much smaller structures.<\/p>\n
\u201cShorter wavelengths matter because you can use them to make higher resolution microscopes,\u201d Murnane said.<\/p>\n
But generating stable and powerful light in this region has proven difficult because most materials strongly absorb it.<\/p>\n
To overcome this challenge, the team combined red and blue laser beams and passed them through a specialized chamber called an anti-resonant hollow core fiber.<\/p>\n
Inside the fiber, the laser light interacts with xenon gas atoms. The atoms absorb the incoming light and re-emit it at much shorter wavelengths, producing vacuum ultraviolet radiation.<\/p>\n
\u201cTo our knowledge, no other approach, either at big or small facilities, has the VUV power levels, tuning ranges and coherence that our new approach has shown,\u201d Murnane said.<\/p>\n
Clocks beyond atomic precision<\/p>\n
The laser could also help build practical nuclear clocks, a long-sought technology that measures time using transitions inside atomic nuclei rather than electrons.<\/p>\n
These clocks would rely on thorium atoms, which oscillate in energy when illuminated with light at a specific wavelength.<\/p>\n
Murnane explained that thorium<\/a> atoms \u201ctick\u201d only when exposed to light at 148.3821 nanometers, a wavelength that falls within the vacuum ultraviolet range.<\/p>\n Today, producing this light typically requires room-sized laser systems. A compact tabletop source could make nuclear clocks more practical and portable.<\/p>\n Such clocks could enable navigation without GPS<\/a>, improve space missions, and support searches for planets beyond our solar system.<\/p>\n