“…[2][3][4][5][6][7] For instance, there is great interest in developing methods to measure the thickness of a sample, either with higher resolutions or straight forward implementations. [8][9][10][11] While there are well established contact-methods with remarkable resolution, [12][13][14][15][16][17][18] optical methods are in general preferable due to their non-contact nature and improved speed. 19 Approaches include chromatic confocal microscopy, 20 phase measuring deflectometry, 21,22 phase shifting interferometry, 23 digital holographic microscopy.…”