Adjustable and stable beam profile generation in a Yb:YAG thin-disk laser

Abstract

We present a Yb:YAG thin-disk laser with an adjustable and stable beam profile. A double-cavity geometry with an acousto-optic modulator (AOM) makes the spatial separation of the gain area, in which the central and external parts are used for L G 00 and L G 01 mode generation, respectively. By changing the loss of the AOM, the beam profile of the primary cavity is adjustable from annularity to flat-top continuously. At input pump power of 44 W, 8.5 W annular, 11.1 W shallow crater-shaped, and 12.1 W flat-topped modes were obtained. Moreover, the thin-disk laser with a multi-pass pumping scheme not only improves thermal management, but also minimizes depolarization loss, allowing the optimization of mode stability and laser performances. This Letter implies that a high-power laser with an adjustable and stable beam profile can be implemented via this scheme.

Controlled Generation of High‐Purity Scalar Orbital Angular Momentum States from a High‐Power Single‐Crystal Fiber Laser

“…[15,31] Figure 6 shows the progression in the development of high-power scalar vortex lasers with different OAM states. [24][25][26]29, Most current studies have focused on the lowest-order OAM state, which shows an evident inverse relationship between the power level and the topological charge of l. This study, in which we achieved the highest power level to date for both low-and high-order states, advances the research on scalar vortex lasers in terms of reaching new power levels. Although there is an inevitable slight degradation in laser performance at higher orders (l > 8) that requires a higher number of SFOC steps and therefore introduces higher scattering and diffraction losses, the high gain of the SCF enables a higher output power than those of the reported OAM lasers.…”

“…[ 15,31 ] Figure shows the progression in the development of high‐power scalar vortex lasers with different OAM states. [ 24–26,29,41–61 ] Most current studies have focused on the lowest‐order OAM state, which shows an evident inverse relationship between the power level and the topological charge of l . This study, in which we achieved the highest power level to date for both low‐ and high‐order states, advances the research on scalar vortex lasers in terms of reaching new power levels.…”

“…[15] Phase modulation switching from external to internal cavity provides a straightforward approach for generating controllable OAM states [20][21][22] or even OAM arrays, [23] such as by inserting a spatial light modulator (SLM), [20] a waveplate in combination with a q-plate, [21] a J-plate, [22] or a metasurface array [23] into the cavity to achieve helical or geometric phase control. Another approach is based on amplitude tailoring using annular beam pumping, [24] double-cavity configuration, [25] or intracavity spot defects [26] to produce only mode-matched LG beams. However, the degeneracy of the azimuthal modes (±l) in such cavities generally results in a zero-average OAM state, thereby requiring additional symmetry breaking to select the defined helicity.…”

Acousto-optic modulator-based bi-frequency interferometer for quantum technology

“…AOMs have been used in various applications, such as stabilizing output power, reducing linewidth, and shaping the spatial profile of a laser beam. [2][3][4] . AOMs can be exploited to realize active optical tweezers and ultrashort pulse picking [5,6] .…”