The CS100 is a three-channel bridge system which uses capacitance micrometers and PZT acuators, incorporated into the etalon, to monitor and correct errors in mirror parallelism and spacing. Two channels control parallelism and the third maintains spacing by referencing the cavity length-sensing capacitor to a high stability standard referen ce capacitor, also located in the etalon. Because this is a closed-loop system, non-linearity and hysteresis in the PZT drive are eliminated entirely, as of course are drifts in cavity parallelism and spacing. The CS100 can be operated manually from front panel controls, or under computer control using either the IEEE-488 or RS232 interfaces, or the analog drive input.

 

The CS100 will control the spacing and parallelism of an ET etalon to better than 0.01% o f a Free Sp ectral Range (FSR). The stability of a transmitted wavelength will depend on the ambient environment, and can b e as good as 1 part in 10¹º if the etalon is mounted in the optional sealed cell and the system carefully temperature controlled. Under either computer or manual control, the CS100 allows random access tuning of an ET-Series II etalon over its spectral range with sub-millisecond response time.

The CS100 Controller.