A scanning mirror Fabry-Perot Interferometer
(sFPI) was designed, built, and implemented to
measure the modes of a laser beam. It has an estimated
finesse of 522 and free spectral range of 3.75 GHz with
a resolution bandwidth of 24 MHz. A piezoelectric device
will change the spacing of the mirrors, allowing scanning
across multiple free spectral ranges. A voltage-source
driver provides a controllable signal to a piezoelectric
device. The spectral frequency content will be captured
by a photo-detector and amplified by a trans-impedance
amplifier. This can be analyzed one of two ways. Either
sent to a micro-controller-computer pair which processes,
displays, and stores this data locally on a hard disk, or
sampled by an oscilloscope which can take the place of the
micro-controller.
