Fig. 4
a Plot of first order diffraction efficiency at 532 nm from the 5 % IAB/APC film during two-beam grating creation at 532 nm. The intensity from each beam was 3.2 mW/mm2. b Plot of the first order diffraction efficiency at 655 nm after the grating was created and when there is a single 532-nm beam intensity of 111 μW/mm2 between 61 and 455 s (the region between the vertical dashed lines)