Diffraction by m- bonacci gratings

Abstract

We present a simple diffraction experiment with m-bonacci gratings as a new interesting generalization of the Fibonacci ones. Diffraction by these nonconventional structures is proposed as a motivational strategy to introduce students to basic research activities. The Fraunhofer diffraction patterns are obtained with the standard equipment present in most undergraduate physics labs and are compared with those obtained with regular periodic gratings. We show that m-bonacci gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which positions are related to the concept of a generalized golden mean. A very good agreement is obtained between experimental and numerical results and the students' feedback is discussed.

The Generation of Equal-Intensity and Multi-Focus Optical Vortices by a Composite Spiral Zone Plate

“…Hence, based on the conventional SZPs, in recent years, researchers have investigated modified SZPs to achieve optical vortices with various physical characteristic to satisfy different applications. For current multi-focus research, the application of some aperiodic structures such as Cantor, Fibonacci and Thue-Morse sequences in diffractive elements has attracted considerable attention recently [29][30][31][32][33][34][35][36][37][38][39][40]. For instance, by combing the Cantor sequence with conventional SZPs, sequence optical vortices with a series of subsidiary foci can be generated at the primary focal plane [41].…”

The generalized mean zone plate

“…The modified Thue-Morse zone plate [19,20] generates twin foci with a position ratio of 5/3. The m-bonacci gratings [21] and m-bonacci zone plates [12] can generate two peaks with a position ratio related to the m-golden mean. However, the above mentioned diffractive optical elements generate two foci with a few limited position ratios only.…”