Efficient laser gives yellow light

17 Jun 2002

A team of researchers from Macquarie University, Australia, has made an efficient all solid-state yellow laser that produces a Q-switched average power output of 1.2 watts.

The 578 nanometre light signal has been produced by Raman shifting and then frequency-doubling the output from a diode-pumped Nd:YAG crystal. The efficiency of the light conversion is as high as 33% and the researchers believe that this performance could be improved by decreasing the losses inside the laser head.

The Nd:YAG laser produces light at 1064 nanometres. A crystal of LiIO₃ in the laser cavity shifts this to 1155 nanometres and then a crystal of LiB₃O₅ doubles the frequency to give the required yellow wavelength.

Medical researchers are interested in lasers at 578 nanometres because this wavelength corresponds to one of the absorption bands of haemoglobin. The laser was described in the 1 November 1999 issue of Optics Letters.

SH