Multilevel Diffractive Optical Elements for high-power laser beam shaping have been designed and produced. The originality of the proposed approach rests on the realization of four phase levels reflection elements with a single etching step. Thus, if the phase change of 270° is obtained by etching a pixel element, intermediary phase difference is obtained by etching subwavelength structures of the same height with appropriate filling factor. Sizing of the subwavelength gratings required with this theory has been carry out for TE and TM polarized radiation with a rigorous electromagnetic model, the Finite Difference Time Domain method. In a first step, a test component has been realized using photolithography to validate the sizing of the subwavelength gratings. In a second step we have adapted a specific fabrication tool based on laser ablation and direct writing for greater flexibility. Characterization has been carried out with Coherence Probe Microscopy. The technique has been applied to the fabrication of a diffractive element used with a high-power CO2 laser beam for surface marking.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.