Mode-matched phase diffractive optical element for detecting laser modes with spiral phases

Abstract

A new type of diffractive optical element for detecting and measuring the power distribution of transverse modes emanating from radially symmetric laser resonators is presented. It is based on a relatively simple straightforward design of a phase-only diffractive optical element that serves as a matched filter, which correlates between specific prerecorded transverse modes with a certain azimuthal mode order and those in the incident laser light. Computer simulations supported by experimental results demonstrate how such elements can accurately detect modes with spiral phases and provide quantitative results on the modal power distribution.

Quantum field theory for coherent photons: isomorphism between Stokes parameters and spin expectation values

“…Then, we found that the splitting of spin and orbital angular momentum is possible in the waveguide, and the splitting is justified as far as the ray is sufficiently collimated to justify the finite mode profile, which induces a small longitudinal component to allow the splitting [20]. If the condition is satisfied, we can treat orbital angular momentum as an independent degree of freedom from spin to form structured lights [12,40,46,47,[75][76][77][78][79][80][81][82][83][84][85]94,95,100,101].…”

Generating function approach for creation of coherent multimode beams by diffractive optics

“…Note that the series of modes in the generating function of Equation (7) have fixed l, different p values, feature a common angular term expðilÞ and differ in circularly symmetric terms. Therefore, the GF of Equation (7) provide a series of Laguerre-Gaussian modes with running radial orders p and fixed optical orbital momentum order l. Alternative series with running l and fixed p ¼ 0 have already been generated by means of a phase nonlinearity method [15,16].…”

“…Papers [15,16] linked linear Dammann-type diffraction gratings with a helical (spiral) phase pattern, expðilÞ, to obtain phase-only GF in a specific case, with p ¼ 0, suitable when the modes do not depend at all on polar radius. In contrast, in our case GF are substantially complex valued functions, comprising modes with p 6 ¼ 0.…”

“…The concept of GF in optics has been extensively studied theoretically by Bastiaans and Alieva [14] and others [5], showing advantages in the description of light propagation and accessing closedform equations for various multimode beams. Papers [15,16] report the implementation of GF in the case of helical (spiral) modes. Generation of separated Laguerre-Gaussian modes is reported in [17,18].…”

Generating Function Approach for the Synthesis of Multichannel Spatial Filters by Diffractive Optics

“…where   provides series of Laguerre-Gaussian modes with running radial orders p and fixed optical orbital momentum order l , whereas alternative series with running l and fixed p =0 were already generated with a phase nonlinearity method [5]. To create a phase-only DOE with encoded binary phase function , for a complex GF, we exploited a complex-tophase encoding procedure of digital holography [4] .…”