Nonlinear confocal positioner for micron-scale target alignment.

This paper presents a novel target positioner system that exhibits high sensitivity and accuracy. Specifically, the system is capable of precisely locating rough target surfaces within a micron-scale in the focal plane. The high sensitivity comes from the nonlinear detection scheme which uses the two-photon-absorption process in a Si-photodiode and a CMOS sensor at 1550 [nm].

High accuracy astigmatic-focusing system for laser targets.

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/. 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.

Direct inversion methods for spectral amplitude modulation of femtosecond pulses.

In the present work, we applied an amplitude-spatial light modulator to shape the spectral amplitude of femtosecond pulses in a single step, without an iterative algorithm, by using an inversion method defined as the generalized retardance function. Additionally, we also present a single step method to shape the intensity profile defined as the influence matrix. Numerical and experimental results are presented for both methods.