||Traditionally, the diffractive optical element (ODE) is made by using the multiple binary-level lithography processes to enhance the diffractive efficiency. Due to the multiple exposures, the manufactory error will be included and more complicate processes is need to be considered. Therefore, to overcome these problems, the grey level mask can be used, in which only one exposure is needed to fabricate the optical element.|
This project presents that a laser machine with light intensity modulation to fabricate grey level masks. In the writer system, a solid-state laser with the power of 180 mw is used as the working light source. The processed target is laser direct write glass developed by the Canyon Material company. An acoustic-optics modulator (AOM) is used to modulate the laser intensity. To make sure the result of the processed mask, a measurement system is built. The laser direct writer system is already out of the binary methods to manufacture optical mask. The optical elements designer can use the LDW system to design any appropriate mask. Thus, the LDW system is a quite useful system for the ODEs.
|| W. Däschner, P. Long, M. Larsson, et al., “Fabrication of diffractive optical elements using a single optical exposure with a grey level mask,” J. Vac. Sci. Technol B. 1995;13:2729-2731.|
 廖宏榮, ”雷射刻板機之研製-半導體與微光機電系統之製程母機,” 國立台灣大學應用力學研究所博士論文, 1998。
 曲昌盛, ”灰階光罩微影技術製作繞射光學元件,” 光訊, 1999;80:23-27。
 E. Kely, F. S. U. Jena, M. Platz, et al., ”Continuous profile writing by electron and optical lithography,” Microelectronic Engineering 1997;34:261-298.
 W. Däschner, M. Larsson, and S. H. Lee, ”Fabrication of monolithic diffractive optical elements by the use of e-beam direct write on an analog resist and a single chemically assisted ion-beam-etching step,” Applied Optics 1995;34:2534-2539.
 M. R. Wang and H. Su, “Laser direct-write grey-level mask and one-step etching for diffractive microlens fabrication,” Applied Optics 1998;37:7568-7576.
 W. Däschner, P. Long, R. Stein, et al., “Cost-effective mass fabrication of multilevel diffractive optical elements by use of a single optical exposure with a grey-scale mask on high-energy beam-sensitive glass,” Applied Optics 1997;36:4675-4680.
 V. Korolkov, A. Malyshev, A. Poleshchuk, et al., “Fabrication of grey-scale masks and diffractive optical elements with LDW-glass,” SPIE 2001;4440:73-84.
 V. Korolkov, R. Shimansky, A. Poleshchuk, et al., ”Requirements and approaches to adapting laser writers for fabrication of grey-scale masks,” SPIE 2001;4440:256-267.
 林俊廷, 林烜輝, 周正三, 張哲瑋, 林暉雄, “微凹面型光柵分光元件的分析與應用,” 台灣光電研討會, 高雄, 2001;295-297。
 J. G. Proakis and D. G. Manolokis, Digital Signal Processing Principles, Algorithm, and Application：3rd edit, Prentice Hall, 1996.
 R. C. Gonzales and R. E. Woods, Digital Image Processing, Addison Wesley, 1992.
 F. A. Jenkins and H. E. White, Fundamentals of Optics：4th edit, McGraw-Hill, 1981.