LDLS sheds light on analytical-sciences applications

Today’s cutting-edge research and manufacturing applications in the life sciences and materials sciences need light sources capable of delivering bright and highly stable light over long lifetimes. A new light-source technology has been developed that can deliver ultrahigh brightness over a broad wavelength band (170–2100 nm) for spectroscopy and other uses, making it a cost-effective, longer-lifetime alternative to conventional deuterium lamps (D2), tungsten-halogen (TH) lamps, and short-arc xenon (Xe) lamps. This new light source, developed by Energetiq Technology and called the laser-driven light source (LDLS), has a much longer lifetime—typically ten times that of traditional lamps—and is more stable than its conventional counterparts, due to the elimination of interactions between a high-temperature plasma and tungsten electrodes. Conventional light sources Many of today’s spectroscopic and other analytical instruments require high-brightness, broadband light sources to make spectral measurements that help determine the composition or structure of samples under study. Traditional light sources do not cover the complete spectral range of interest, which is typically from the deep-ultraviolet (UV), through the visible, and into the near-infrared (NIR; about 170– 1100 nm). For example, an analytical instrument will typically use a combination of a shine-through D2 lamp with a TH or a Xe lamp for broadband applications. The use of multiple lamps in one instrument causes complexity in the optical design, leads to inefficient use of the light, and adds extra cost. In addition, the lifetime of those lamps is typically 500–2000 h, requiring frequent lamp replacement and instrument recalibration. In the deep-UV wavelengths, traditional lamps have low brightness (radiance), which puts additional constraints on instrument capabilities. Instruments using multiple lamps must deal with such issues as mismatched lamp spectra, low throughput or sensitivity due to the low brightness, and spectrum changes as individual lamps age differently. In many cases, the complexity and cost drive the system designer to use only one lamp, typically a D2 or Xe lamp alone, limiting the instrument in its spectral response and its flexibility in applications. Deuterium lamps with fused-silica windows are UV-emission lamps with a useful wavelength range from 180–380 nm. The emissions are low at wavelengths longer than 380 nm, so a TH or a Xe lamp may be used to provide visible and NIR radiation. An ultrawideband laser-driven light source has the long life and high spatial and spectral stability needed to fulfill demanding requirements in the sciences.