Configurable illumination source for optical metrology and related methods

A method for illuminating a sample, the method comprises:

• illuminating a sample with radiation using an illumination source that comprises a matrix that comprises twenty-five light emitting diodes (LEDs) that are arranged in twelve different sets of LEDs associated with twelve peak wavelength ranges, wherein (i) a first set and a second set have their peak wavelength range within the 400 till 500 nanometer range, (ii) a third set has its peak wavelength range within the 500 till 600 nanometer range, (iii) a fourth set has its peak wavelength range within the 600 till 700 nanometer range, (iv) wherein a fifth set, a sixth and a seventh set have their peak wavelength range within the 700 till 800 nanometer range, (v) an eighth set and a ninth set have their peak wavelength range within the 800 till 900 nanometer range, (vi) a tenth set, an eleventh set and a twelfth set have their peak wavelength range within the 900 till 1000 nanometer range.