The first implementation of a/LCI used a Michelson interferometer, the same model used in the famous Michelson–Morley experiment. The Michelson interferometer splits one beam of light into two paths, one reference path and one sampling path, and recombines them again to produce a waveform resulting from interference. The difference between the reference beam and the sampling beam thus reveal the properties of the sample in the way it scatters light.
The early a/LCI device used a movable mirror and lens in the reference arm so that researchers could replicate different angles and depths in the reference beam as they occurred in the collected backscattered light. This allowed isolation of the backscattered light at varying depths of reflection in the sample. 
In order to transform the data into measurements of cell structure, angular scattering distributions are then compared to the predictions of Mie theory—which calculates the size of spheres relative to their light scattering patterns.
The a/LCI technique was first validated in studies of polystyrene microspheres, the sizes of which were known and relatively homogeneous. A later study expanded the signal processing method to compensate for the nonspherical and inhomogeneous nature of cell nuclei.
This early system required up to 40 minutes to acquire the data for a 1 mm² point in a sample, but proved the feasibility of the idea.