Blue Laser Diodes Used in Spectroscopy

A group at Bonn University in Germany has employed a laser spectrometer based on the InGaN blue laser diodes produced by Nichia Chemical Industries Ltd. in Anan, Japan. The device incorporated a turnkey commercial laser system developed by TuiOptics GmbH of Munich, Germany, to perform continuous-wave spectroscopy at 410 nm.

The researchers tested the device by distinguishing the resonance frequencies of ¹¹³In and ¹¹⁵In isotopes. The laser excited a beam of indium atoms, and a photomultiplier collected the blue photons that were emitted. Robert Wynands, a member of the team, said the device replaces the university's more complicated, frequency-doubled 820-nm laser diode system and provides an output nearly 100 times more powerful than that of the previous system.

The blue light source will find use in trace gas analysis, which typically uses infrared transitions to detect concentrations. TuiOptics noted that many atoms, molecules and ions display stronger absorption in the blue to ultraviolet wavelengths. The company predicted that blue diode laser spectroscopy will move to field applications in stable, portable systems.