Figure 7
Experimental setup schematic. A polarization controlled femtosecond laser beam, centered at 808 nm with 3 kHz repetition rate, 38 fs pulse width, and 1.67 mJ pulse energy is incident on a spatial light modulator (SLM). The polarization control is achieved using a polarizer (P) and a half-wave plate (HWP). An iris is used for mode selection to isolate any desired LG\(_{\ell ,p}\) before it is propagated to plane (i). A tilted lens (TL), with \(\alpha\) being the tilt angle, transforms the LG\(_{\ell ,p}\) modes into generalized HLG (gHLG\(_{\ell ,p}^{\alpha }\)) mode. A beam splitter (BS, not illustrated) is placed after the TL to image the intensity profile at the plane (ii). The upconverted beam through a \(\beta\)–Barium Borate crystal (BBO) is then separated from the fundamental beam using a bandpass filter (405 ± 10 nm). The SH beam is inverse Fourier transformed by lens L\(_1\) and imaged by Detector 1, plane (iv). Lenses L\(_2\), together with L\(_1\) are used to transfer plane (iii) onto Detector 2.
