Fig. 2: Manipulation of MOD.
From: 3D ultra-broadband optically dispersive microregions in lithium niobate
a Manipulation of the spectrophotometric direction of MOD signals in the crystal matrix. θ and α indicate wedge angles applied for rotating dispersive microregions in 3D space. Blue arrow indicates the writing direction. E indicates the laser polarization. Scale bar: 200 µm. b Spectral characterization of a dispersive microregion. Inset: representative spectrum test points in the dispersive microregion. Scale bar: 100 µm. c Interval of interference fringes as a function of wavelength under different wedge angles. Inset: experimentally imaged interference fringes by using 590 nm illumination. Scale bar: 100 µm. d Relative positions of the interference fringes of different wavelengths along the laser scanning direction. Colored lines represent the interference fringes of several representative wavelengths. e Spectrophotometric length as a function of the wedge angle. Insets: experimental results obtained by using corresponding wedge angles on the theoretical curve. Scale bar: 100 µm. f Wedge thickness as a function of wavelength. Insets: experimentally generated ultra-compact MOD (top-left) and schematic of a dispersive microregion (middle).
