Modulo Quatro

Description

MCRQ multiplied

The Quatro features four Multi-Channel Random Quadrature measurement channels, each an independent measurement point. MCRQ does not rely on a standard quadrature detection scheme (which requires the detection of two complimentary signals with a 90° phase difference). Instead, it takes advantage of the random optical phase distribution, assuming that statistically half of signals registered by the photodetectors are in- quadrature and half are out-of-quadrature.

In the Modulo design, the combined sample and reference beans necessary for interferometry are directed straight onto a single detector array which collects both the vertically and horizontally polarized components, allowing us to make an instrument that is remarkably compact per measurement channel, all while remaining both highly sensitive and rugged.

As in the Quartet, the signals from the detector arrays are demodulated separately then summed together. This way the overall sensitivity of the measured signal remains high without the need for stabilization, as the out-of- quadrature signals will not contribute to the resulting signal.

One or Multiple Optical Heads

A multi-point Modulo can be built to run multiple closely spaced measurement points through a single optical head or feature four separate optical heads. Closely spaced measurement points drastically increase scan speeds (x 4) and reduces localized heating from the optical probe (the heat is distributed among measurement points). On the other hand, multiple optical heads provide a broader measurement range, as well as the possibility of measuring at different angles, such as to extract the 3D component.