| Abstract [eng] |
Diffractive optical elements (DOE) are phase elements that operate by means of interference and diffraction to produce arbitrary distributions of light or to aid in the design of optical systems. Due to the special element profile design, DOE effectively shape and split laser beams. In this work it is discussed how to calculate such elements profiles and is shown how to fabricate difractive optical elements by the direct laser writting photolithographical method. Using photoresist I and HF acid a beam splitter (1x3) was made on borosilicate (ROTH) glass. The efficiency of such element was more than 70%. This fabrication method was used on BK7 glass, but glass etching rate was irregular, so another photoresist II and BOF acid was chosen. Although the etched glass profile had better quality than using HF and photoresist I, results were still not suitable for high efficiency DOE fabrication, therefore, BK7 glass was replaced with UVFS glass. Under the same conditions UVFS samples exhibited were much more repeatable. In this way, it was possible to produce high efficiency (more than 70%) 1x3 beam splitter. Also, photoresist II and BOF were tried on borosilicate (ROTH) glass, which also exhibited repeatable results, and enabled the fabrication of 1x2 beam splitter (efficiency - more than 78%) and beam sampler (efficiency - more than 95%) . |
