Creating Airy beams employing a transmissive spatial light modulator

TL;DR

This paper introduces two innovative methods for generating optical Airy beams using transmissive spatial light modulators, eliminating the need for physical lenses and enabling more compact setups, with validated experimental and simulation results.

Contribution

The paper presents two novel lensless methods for creating Airy beams with transmissive SLMs, including a quantitative analysis of beam deflection and direct modulation of the Airy function.

Findings

First method produces Airy beams with a unique deflection formula validated by experiments.

Second method enables direct transfer of the Airy function onto SLM for immediate beam generation.

Both methods result in more compact setups compared to traditional lens-based systems.

Abstract

We present a detailed study of two novel methods for shaping the light optical wavefront by employing a transmissive spatial light modulator (SLM). Conventionally, optical Airy beams are created by employing SLMs in the so-called all phase mode. In the first method, a numerically simulated lens phase distribution is loaded directly onto the SLM, together with the cubic phase distribution. An Airy beam is generated at the focal plane of the numerical lens. We provide for the first time a quantitative properties of the formed Airy beam. We derive the formula for deflection of the intensity maximum of the so formed Airy beam, which is different to the quadratic deflection typical of Airy beams. We cross-validate the derived formula by both simulations and experiment. The second method is based on the fact that a system consisting of a transmissive SLM sandwiched between two polarisers can create a transmission function with negative values. This observation alone has the potential for various other wavefront modulations where the transmission function requires negative values. As an example for this method, we demonstrate that a wavefront can be modulated by passing the SLM system with transmission function with negative values by loading an Airy function distribution directly onto SLM. Since the Airy function is a real-valued function but also with negative values, an Airy beam can be generated by direct transfer of the Airy function distribution onto such an SLM system. In this way, an Airy beam is generated immediately behind the SLM. As both new methods do not employ a physical lens, the two setups are more compact than conventional setups for creating Airy beams. We compare the performance of the two novel methods and the properties of the created Airy beams.