Voltage-controlled colours

The optical shutter described above can function as a voltage-controlled colour filter. The PLZT is again of the slim-loop quadratic variety, and the polarizer-PLZT-analyser configuration as for the shutter. 

For easy identification and prompt maintenance it is mandatory to segregate all control wires when they are carrying more than one control supply (e.g. at different voltages and both a.c. and d.c.), and run them in separate bunches. The control wires must also be of different colours for different control supplies. The colour codes have been standardized for different control supplies (refer to lEC 60445). 

Figure 1 shows a rotatable Polaroid sheet, p, for determination of the emission polarization with respect to v Bandpass and coloured glass cut off filters replace this Polaroid sheet for coarse spectral analysis. Output from a bialkali cathode photomultiplier tube, pmt, is monitored by a photon counter signal averager at the hexapole modulation frequency and stored on a microcomputer that also controls the various field voltages and polaroid sheet positions. 

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