It should be noted that no evanescent field can be generated when the beam is incident at the tip of a groove as this part of the chip is parallel to the top surface. The bottom of the groove also needs to be avoided for practical reasons: here, the beam is spatially split leading to two focal spots far apart. However, when these areas are avoided the results of the FDTD study confirm that for real-world sample preparation and measurement situations the carriers should perform optically similar to conventional ZnSe prisms.