Method and system for depth-dependent measurements of dynamic properties

Abstract

The invention provides a method for determining a material property of a sample (50) using a photoelectric detector (120), wherein the photoelectric detector (120) has a frame rate RD and comprises an array (122) comprising 11 pixels (125), Wherein the frame rate RD Z 10 kHz, wherein n 2 100, and wherein the method comprises: providing measurement radiation (111) along a measurement path (10) and along a reference path (20), Wherein the measurement 10 radiation (111) is coherent, Wherein the measurement radiation (111) comprises m measurement phases (40), Wherein m Z 2, wherein the measurement phases (40) have a measurement duration (Tm), wherein RD*Tm Z 100, wherein each measurement phase (40) comprises a frequency sweep (45) over a frequency range selected from the range of 10 — 1000 GHz, Wherein the measurement path (10) enters the sample (50) at an entrance location (51), 15 passes through at least part of the sample (50), and exits the sample (50) at an exit location (52), Wherein the entrance location (51) and the exit location (52) are separated by at most 5 cm, Wherein the measurement path (10) downstream of the sample (50) differs from the measurement path (10) upstream of the sample (50), and Wherein the measurement path (10) and the reference path (20) merge into a combined path (30) downstream of the sample (50), 20 detecting a spectral interference pattern of the measurement radiation (1 1 1) travelling along the combined path (30) using the photoelectric detector (120) to provide a spectral signal (Sn…) for each of the m measurement phases (40) and the 11 pixels (125), and determining the material property based on the spectral signals (Sn…)