如下：“Similar to the above is the VCSEL with the petal−shaped holey structure [Fig. 6(d)] [67]. As previously, increased scattering losses of higher order modes, as compared with that of the fundamental mode, are achieved in the petal holey structure with the larger hole number. Then, about 1 mW of the SFM output is achieved in the above 6−μm VCSEL emitting the 850−nm radiation (line 42). Relatively low output is a result of high optical losses introduced by the mode discrimination mechanism, surprisingly high as com− pared with the previous similar structure. However, divergence of the output beam of this device is very low (3.2°) which results from enlarged lateral dimension of the hole along the radial direction outwards from the centre [Fig. 6(e)], so the hole depth is gradually increased. Resulting graded index profile in the top DBR broadens the optical field which leads to this ultra−narrow beam divergence [67].”
文章作者W. NAKWASKI介绍：
Professor W. Nakwaski, the director of the Institute of Physics at the Technical University of Lodz, Poland, is an internationally recognized scientist working over 25 years in semiconductor optoelectronics. He has received MSc in both Electrical Engineering (in 1971 from the Technical University of Lodz) and Physics (in 1973 from the Lodz University), PhD and DSc in Electrical Engineering (in 1976 and 1985, respectively, from the Institute of Electron Technology in Warsaw) and the Title Professor in Physics (in 1996 from Aleksander Kwasniewski, the President of Poland).
Being both the physicist and the electrical engineer, Professor W. Nakwaski is using in his research modern methods of computer physics to investigate performance of various optoelectronic devices, mostly semiconductor diode lasers. In particular, he has been simulating operation of various diode lasers and laser arrays in full complexity of all interrelated physical phenomena crucial for their proper work. Using the above simulations, he has been investigating an impact of various construction parameters on laser important performance characteristics, receiving essential optimization suggestions for laser designers. He has published his research results in over 300 regular and conference papers. He is also an co-author of two scientific books devoted to physics of semiconductor lasers ["Semiconductor Lasers" (in Polish), Polish Scientific Publishers (PWN), Warsaw 1985 and "Physics of Semiconductor Lasers", North Holland, Amsterdam 1991], three chapters in scientific books and two patents.
Professor W. Nakwaski has spent over 4 years in the Center for High Technology Materials at the University of New Mexico, Albuquerque, USA (1 year as a Senior Visiting Scientist and over 3 years as a Research Associate Professor). Now he is a Full Professor in the Institute of Physics, Technical University of Lodz, Poland and is supervising the Laboratory of Computer Physics at this institute..
Professor W. Nakwaski received 7 times (in 1978, 1980, 1984, 1987, 1990, 1999 and 2002) the Prize of the Minister of National Education in Poland for scientific achievements.
