Nichia developed blue green semiconductor laser oscillation wavelength 488nm

Nichia developed continuous oscillation when the center wavelength of blue green semiconductor laser element 488nm, a 08 year in March to start sample delivery. The products in the use of GaN semiconductor laser components and has been put into operation in the varieties, the longest wavelength.

This product is used to replace the Ar (AR) laser used in the research and development of biotechnology. In this field, Ar laser is used as the excitation source of fluorescence analysis, that is, using the laser to irradiate the DNA with fluorescent material to quantitatively analyze the luminescence of the material. According to Nichia, Ar laser energy conversion efficiency of only a few percentage points, so a large amount of heat, cooling system is large, so has been eager to reduce the size of the laser irradiation device. The blue green semiconductor laser will be issued to the efficiency of energy conversion to 13%, can achieve miniaturization of laser irradiation device. In addition, Nichia also referred to the development of the component can be compared with the characteristics of high speed modulated Ar laser. In being held in the United States Shengnuosai "Photonics West", in January 22nd the company began to show the product in the booth.

The output power of the sample which has been supplied is 5mW. The driving current is 71mA and the driving voltage is 5.3V. The threshold current of the blue green semiconductor laser is 49mA and the threshold voltage is 5.0V. Continuous oscillation, the output power of 5mW, the card can be stable at 1000 degrees Celsius +25 hours. The estimated life is more than 10 thousand hours (initial current value reaches 1.3 times). The first and only 5mW model, 20mW model "is not impossible" (Nichia), is currently doing pre production development. Although not described in detail, but the 20mW model is likely to be compared with the 5mW model, the characteristics of the optical output power changed when the input current.

In order to realize the central wavelength 488nm, the ratio of In in the light emitting layer is improved. However, due to the difference of lattice constants, the higher the In ratio is, the more defects in the crystals will be, which results in the decrease of the crystalline quality and the difficulty of luminescence. This time, the optimization of the growth of the crystal, without increasing too much density can improve the ratio of In. In addition, in order to make the light produced in the crystallization process is not easy to absorb, in the light-emitting layer structure and so on also made improvements.

The Nichia chemical industries with existing products in the polar surface of GaN plate is formed on the light emitting element structure. At present, in the field of GaN semiconductor laser components, it is a hot spot to realize the research of green semiconductor laser. In the aspect of large wavelength, it is usually to improve the In ratio in the light emitting layer, and as mentioned above, the crystal defects will increase, and the efficiency will decrease due to the enhancement of the piezoelectric field. In recent years, the study of the formation of light emitting elements on the non-polar surface of GaN substrate has been started in order to reduce the piezoelectric field. Nichia chemical industries not only in non-polar surface, also committed to the research on large wavelength in the polar plane.

Source: Nikkei BP