The colour of data

Manufacturers today are looking forways to pack in more data in laserdiscs. But the most commonly usedlasers emit red light which has alonger wavelength compared to bluelight. Attempts to make a blue semiconductor laser have so far not beenvery successful.

Now, a team of scientists fromthe Nichia Chemical Industries,Japan, have built a violet semiconductor laser using an alloy calledgallium nitride. Successful trialswill mean that the data packed in acompact disc will almost double(Science, Vo1271,No 5247).