Figure 1From: Porous silicon Bloch surface and sub-surface wave structure for simultaneous detection of small and large moleculesSEM image and etch parameters of PSi BSW/BSSW sensor. (a) SEM cross-sectional image of PSi BSW/BSSW sensor. Refractive index profiles of (b) step and (c) gradient index BSW/BSSW sensors where the numbers shown above each layer represent the etch current (mA/cm2) and etch time (s), respectively. The field intensity of the BSW mode (red) and 1st BSSW modes (blue) are shown within the corresponding layers of the sensor.Back to article page