Efficient generation of Hermite-Gauss and Ince-Gauss beams through kinoform phase elements

Integrated optical phased array with on-chip amplification enabling programmable beam shaping

We present an integrated optical phased array (OPA) which embeds in-line optical amplifiers and phase modulators to provide beam-forming capability with gain and beam steering in the 1465-1590 nm wavelength range. We demonstrate up to 21.5 dB net on-chip gain and up to 35.5 mW optical output power. The OPA circuit is based on an InP photonic integration platform and features the highest measured on-chip gain and output power level recorded in an active OPA (i.e., with amplification), to the best of our knowledge. Furthermore, the OPA enables the independent control of both amplitude and phase in its arms and through this we demonstrate programmable beam shaping for two cases. First, we carried out a Gaussian apodization of the power distribution profile in the OPA emitter waveguides, leading to 19.8 dB sidelobe suppression in the far-field beam, which is the highest value recorded for active OPAs, and then we demonstrated beam forming of 0th, 1st, and 2nd order 1D Hermite-Gaussian beams in free-space.

Generation of combined half-integer Bessel-like beams using synthetic phase holograms

We discuss the generation of combined half-integer Bessel-like (CHB) beams using synthetic phase holograms (SPHs). We assess the efficiency and accuracy of the SPHs, in the task of generating CHB beams. The proposal is illustrated by the implementation of CHB beams, which are experimentally generated in a setup based on a phase spatial light modulator. Also, we analyze, numerically and experimentally, the propagation of the generated CHB beams. As the main result, the SPHs are able to generate several CHB beams with relatively high accuracy. Additionally, it is obtained that the efficiency values of the SPHs are close to the theoretical predictions.

Generation of Ince–Gaussian Beams Using Azocarbazole Polymer CGH

Ince–Gaussian beams, defined as a solution to a wave equation in elliptical coordinates, have shown great advantages in applications such as optical communication, optical trapping and optical computation. However, to ingress these applications, a compact and scalable method for generating these beams is required. Here, we present a simple method that satisfies the above requirement, and is capable of generating arbitrary Ince–Gaussian beams and their superposed states through a computer-generated hologram of size 1 mm², fabricated on an azocarbazole polymer film. Other structural beams that can be derived from the Ince–Gaussian beam were also successfully generated by changing the elliptical parameters of the Ince–Gaussian beam. The orthogonality relations between different Ince–Gaussian modes were investigated in order to verify applicability in an optical communication regime. The complete python source code for computing the Ince–Gaussian beams and their holograms are also provided.

Generation of vector beams using synthetic phase holograms

We discuss a class of synthetic phase holograms (SPHs) applied to the generation of vector fields. Each SPH encodes the transverse components of the vector field, modulated by different linear phase carriers. Such components, which are spatially separated by the carriers, are modulated by appropriate orthogonal polarizations. A final stage that makes the components collinear allows the generation of the vector field. We assess the efficiency and accuracy of the different SPHs, in the task of generating vector fields. The proposal is illustrated by the implementation of vector Bessel beams, which are experimentally generated in a setup based on a phase spatial light modulator.

Polarization properties of Ince-Gaussian laser beams

A consistent theoretical description of the polarization properties of Ince-Gauss (IG) laser beams is provided by constructing paraxial IG solutions to Maxwell equations. We confirm this description experimentally by recording both the dominant and cross-polarization components. Moreover, by experimentally confirming the evolution of the dominant and cross-polarization components as functions of ellipticity parameters, our paper extends further support to a unified treatment of the three (Laguerre-Gauss, Hermite-Gauss, and IG) families of paraxial laser beams.