Mirrors and other optical devices split, return, and recombine the light beam. Passing through the medium slows that part of the light beam, so the recombined beam is out of phase and produces an interference pattern that carries information about the disturbance. IPCG experiment cells are made of optical glass and silvered on one side to serve as a mirror in the interferometer system that visualizes crystals and conditions around them as they grow inside the cell. In the IPCG, the glass crystal growth cell, only 1 mm thick, is silvered on the back to act as the mirror on the experiment leg of the light path. This is a liquid crystal cell that can retard slightly the horizontal polarized beam without affecting the vertical polarized beam.
Retardation occurs along the plane of an electric voltage applied across the liquid crystals.
A Dove prism folds the light through a 180 deg. The polarizing filter is oriented at 45 deg. The computer, via the waveform generator, controls the phase modulator to produce varying interference patterns. Each fluid handling system is a self-contained plastic assembly enclosing two pairs of 4 mL supply syringes, a waste receptacle, a test cell, and associated plumbing, plus mechanisms to inject the fluids and to position the test cell. Each pair feeds through valves to mix in a T-intersection and then flow into the experiment cell.