An optical signal is injected into a waveguide and ended by a mirror (true Lippman configuration).
Early in 1933, Herbert E. Ives proposed to use a photoelectric device to probe stationary waves to make spectrometric measurements.
[3] In 1995, P. Connes[4] proposed to use the emerging new technology of detectors for three-dimensional Lippmann-based spectrometry.
Following this, a first realization of a very compact spectrometer based on a microoptoelectromechanical system (MOEMS) was reported by Knipp et al. in 2005,[5] but it had a very limited spectral resolution.
In 2004, two French researchers, Etienne Le Coarer from Joseph Fourier University and Pierre Benech from INP Grenoble, coupled sensing elements to the evanescent part of standing waves within a single-mode waveguide.
These nanodots are characterized by an optical index difference with the medium in which the evanescent field is located.
Fellgett's advantage also states that when collecting a spectrum whose measurement noise is dominated by detector noise, a multiplex spectrometer such as a Fourier-transform spectrometer will produce a relative improvement in the signal-to-noise ratio, with respect to an equivalent scanning monochromator, that is approximately equal to the square root of the number of sample points comprising the spectrum.
The Connes advantage states that the wavenumber scale of an interferometer, derived from a helium–neon laser, is more accurate and boasts better long-term stability than the calibration of dispersive instruments.