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 n pixels (125), wherein the
frame rate RD ≥ 10 kHz, wherein n ≥100, and wherein the method comprises: providing measurement
radiation (111) along a measurement path (10) and along a reference path (20), wherein the measurement
radiation (111) is coherent, wherein the measurement
radiation (111) comprises m measurement phases (40), wherein m ≥ 2, wherein the measurement phases (40) have a measurement duration (Tm), wherein RD*Tm≥ 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), 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); detecting a spectral interference pattern of the measurement radiation (111) travelling along the combined path (30) using the photoelectric
detector (120) to provide a spectral
signal (Sm,n) for each of the m measurement phases (40) and the n pixels (125); and determining the material property based on the spectral signals (Sm,n).