Fig. 1: Spatial moulding of ultrashort pulse light based on OCMS waveguide with variable cross-section and RI profile.
From: Precise mode control of laser-written waveguides for broadband, low-dispersion 3D integrated optics
a Conceptual scheme for ultrashort pulses with different central wavelengths (λ1, λ2, λ3) to undergo spatial mode conversion into high-order mode pulses. Schematic illustration of a laser-written waveguide employing the OCMS approach (down inset). b Design diagram of scanline overlapping schemes (upper) for four types of fundamental-mode waveguides with measured index distributions (down) of step (I), GRIN (II), “W”-like (III) and “U”-like (IV), respectively. c–e Optical micrographs (OM) of four fundamental-mode waveguides (left), four higher-order mode waveguides for LP11, LP21, LP31, and LP12 modes (middle) in three typical glasses (Eagle XG, Gorilla 3 and fused silica FS 7980), as well as Raman mappings of four higher-order mode waveguides (right). Scale bars are 10 μm
