What is the Real Color of Blue Laser?

The blue laser is not actually BLUE but violet in color, using the gallium nitride diodes. This blue laser is actually reddish purple for the human eye but its laser dot on white paper turns to blue, the same effect produced by the black light on white surfaces. Blue laser diodes based on indium gallium nitride could often produce true-blue laser colors but it could also produce other colors.

The blue laser is a semiconductor laser diode emitting a radiation wavelength between 360 to 480 nanometers. It is an advanced commercial laser type and is popularly known to be used in optical media, particularly in Blu-ray Discs and HD DVD.

During the late 70’s we had laser discs (LD), the size of more than twice our dinner plates in diameter. Thanks to Sony and Philips that in the 80’s we had our first compact discs. In 1995, Philips, Sony, Toshiba and Time Warner invented the Digital Video Disc which could have a capacity of more than ten times that of the CD. However, in the year 2000, Sony/Philips started to use a new laser diode, the UDO (Ultra Density Optical), with the DVR Blue, that later became the Blu-ray disc. It surpassed the DVD in capacity to more than five times and in terms of data rate to more than three times at 1x.

This development was inevitably attributed to the blue laser. The DVD used the 650-nanometer red laser, while the Blu-ray Disc (BD) uses the 405-nanometer blue laser. As early as the 1960’s, the blue laser was a well sought project, but the gallium nitride (GaN) crystals used as diodes for the blue laser was very hard to manufacture, requiring very high pressures and temperatures, much like producing synthetic diamonds. So researcher tried to use the readily available sapphire but defects (crystallographic defect) were too high. It was not until 1992 when the blue laser was actually invented by a Japanese inventor Shuji Nakamura who started out with the first efficient blue LED (light emitting diode).

It was however, still cluttered with defects to produce a high-power laser. Later, Nakamura was able to use gallium nitride with a higher structural quality developed from the Polish Academy of Sciences in Warsaw, thus producing much lesser crystallographic defects. In 1999, he was able to make a blue laser that yielded 30mW which could last 3,000 hours. Ten years after, the Japanese manufacturers perfected the technology using a sapphire surface covered by a layer of GaN and were able to produced 60mW blue lasers applicable to devices that read high-speed and high-density media such as the Blu-ray disc. Nakamura was awarded the Millennium Technology Prize in 2006 for his achievements.

Blue laser is not only used in optical media but also in telecommunications, medicine, environment research and monitoring, and it is an essential part in electronic equipment especially multimedia. The Play Station 3 which features the use of the Blue-ray format utilizes such type of laser. High-Definition Videos are made possible with the use of blue lasers. Commercial laser projector prices have dropped due to these advances in technology.

Before the end of this decade, many significant advances in technology have given us, in our homes and business enterprises, another new perspective of the world we live in. Blue laser is one of those which made it possible.