Manufacturers today are looking for ways to pack in more data in laser discs. But the most commonly used lasers emit red light which has a longer wavelength compared to blue light. Attempts to make a blue semiconductor laser have so far not been very successful.

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