Abstract

An accurate location of the focal position with respect to a solid target is a key task for different applications, for instance, in laser driven plasma acceleration for x-ray generation where minimum required intensities are above ${10^{14}} \;{\rm W}/{{\rm cm}^2}$. For such practical applications, new approaches for focus location and target delivery techniques are needed to achieve the required intensity, repeatability, and stability. There are different techniques to accomplish the focusing and target positioning task such as interferometry-, microscopy-, astigmatism-, and nonlinear-optics-based techniques, with their respective advantages and limitations. We present improvements of a focusing technique based on an astigmatic method with potential applications where maximum intensity at the target position is necessary. The presented technique demonstrates high accuracy up to 5 µm, below the Rayleigh range, and also its capability to work in rough surfaces targets and tilt tolerance of the target, with respect to the normal of the target surface.

© 2022 Optica Publishing Group

Nonlinear confocal positioner for micron-scale target alignment

J. Delgado-Aguillón, C. Ruiz, M. Rosete-Aguilar, and J. Garduño-Mejía
Opt. Express 31(15) 23746-23753 (2023)

Laser focus positioning method with submicrometer accuracy

Ilya Alexeev, Johannes Strauss, Andreas Gröschl, Kristian Cvecek, and Michael Schmidt
Appl. Opt. 52(3) 415-421 (2013)

Adaptive energy filtering method based on time-domain image sequences for high-accuracy spot target localization

Jingyu Bao, Haiyang Zhan, Ting Sun, Fei Xing, and Zheng You
Appl. Opt. 61(11) 3034-3047 (2022)

Speckle pattern sequential extraction metric for estimating the focus spot size on a remote diffuse target

Zhan Yu, Yuanyang Li, Lisheng Liu, Jin Guo, Tingfeng Wang, and Guoqing Yang
Appl. Opt. 56(32) 8941-8949 (2017)

Modified astigmatic beam technique for laser writing

Jerome Lapointe, Jean-Philippe Bérubé, Albert Dupont, Matthieu Bellec, and Réal Vallée
Appl. Opt. 61(9) 2333-2337 (2022)