Bessel beam generation using a segmented deformable mirror

Abstract

Bessel beams with tunable spot size are desirable for many applications such as laser material processing, optical trapping, and imaging. In this paper, we report experimental and simulation results of using a segmented deformable mirror to generate zero- and higher-order Bessel beams that have a controllable transverse and longitudinal shape. The tilt angle and piston position of the mirror segments are optimized to recreate the phase structure of a reflective axicon. Zero-order Bessel beams are generated at various beam converging angles, and their core diameter, peak intensity, and depth-of-focus are found to agree with the calculated results. By applying a phase ramp along the azimuthal direction, the first-order Bessel beam is generated with the characteristic annular shape. Because deformable mirrors have low absorption and dispersion and operate at a fast frame rate, they are a promising candidate for spatial beam shaping of high-power ultrafast lasers, which are used in material processing applications.

Experimentally simulating the beam shaping capabilities of piston-type deformable mirrors using a liquid crystal spatial light modulator

“…The generation of both zero and higher-order Bessel-Gauss beams have also been reported, whereby a segmented deformable mirror having 37 hexagonal segments in a honeycomb configuration was used. First the deformable mirror was used as a reflective axicon to generate the zeroorder Bessel beam, and then it was programmed to produce a 2 spiral phase for the creation of higher-order Bessel beams [23]. However, these spatial modes are often not of a high fidelity (or correlation) with their desired "true" spatial profile.…”

Wavefront control with high-spatial cartridge-type piezostack deformable mirror

“…There are various correctors which have their own advantages and disadvantages. They are divided into devices with a continuous [15] and segmented [16] reflective surface. According to the principle of operation, they can be divided into: mechanical [17] , membrane [18], MEMS [19] , magnetostrictive [20] , thermally deformable [21] , piezostack [22][23][24][25] , bimorph [26][27][28][29][30][31][32][33] , combined mirrors (using several technologies simultaneously) [34,35] , as well as liquid crystal light modulators [36] , devices with a matrix of micromirrors (DMD technology) [37] or simple tip-tilt stages [38][39][40][41] .…”

Experimentally simulating the beam shaping capabilities of deformable mirrors using a liquid crystal spatial light modulator

“…The generation of both zero and higher-order Bessel-Gauss beams have also been reported, whereby a segmented deformable mirror having 37 hexagonal segments in a honeycomb configuration was used. First the deformable mirror was used as a reflective axicon to generate the zero-order Bessel beam, and then it was programmed to produce a 2π spiral phase for the creation of higher-order Bessel beams [23]. However, these spatial modes are often not of a high fidelity (or correlation) with their desired "true" spatial profile.…”