Improved spectral resolution in time-varying interferometry

J R TORGA; J ANTONACCI; RICARDO DUCHOWITCZ; J ANTONACCI; RICARDO DUCHOWITCZ; E N MOREL; G. ARENAS; E N MOREL; G. ARENAS; J R TORGA

OPTICS AND LASERS IN ENGINEERING

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2018 vol. 110 p. 457 - 461

0143-8166

In this work, we present a procedure that allows increasing the resolution of dynamic length measurements made by spectral interferometry. The proposed schemeleads to obtaining a compact photonic instrument with the ability to measure distances, variations on positions and vibrations with a very high resolution. Thismeasurement system includes a superluminescent source (SLED), a digital spectrometer and a Fizeau interferometer. Spectral data is processed by applying Fourierdomain techniques previously applied in optical coherence tomography. The resolution of the spectral measurement system is determined by the spectrometerbandwidth and the light source employed. A signal is obtained by analysing the time evolution of a single pixel from the spectrometer CCD sensor, which is lateranalysed using time domain interferometry (TDI) techniques. This procedure works by detecting changes in the optical path below those that can be detected byspectral analysis. The original resolution obtained with the solely spectral techniques was 2.2 μm but was improved to 40 nm by complementary analysis of temporalsignals