What Is a PP Slot?

A pp-slot device has a dual slot structure with two electrical terminals. The device is made using a silicon-on-insulator (SiO2) process. The n- and p-doped regions are separated by a gap, which is actuated by applying voltage. The applied bias induces electrostatic fields near the gap region, which bend the lateral beams towards the center beam. The n- and s-type dopants contribute little to the propagation loss, and the optical mode is confined to the slot.

The extrusion slot coating speed can be extended by increasing the concentration of polymer additives. Two common polymer additives are carboxymethylcellulose (CMC) and polyacrylamide (PAA). While polymer concentrations can extend the maximum coating speed, their effect on the minimum wet film thickness is negligible at high coating speeds. Fluid elasticity destroys the smooth coating and creates a coated film with an irregular surface.