Spectrometer with adjustable sensitivity

An optical spectrometer for analysing an input optical signal, said input optical signal being inputted to the spectrometer, the optical spectrometer comprising:

• an optical entrance configured for receiving the input optical signal and for generating a first optical signal, said first optical signal being a diverging beam,
• an optical aperture device configured for receiving the first optical signal derived from the input optical signal, and configured for selecting a portion of said first optical signal to generate a second optical signal exiting said optical aperture device, and
• an optical element configured for receiving on its surface the second optical signal exiting the optical aperture device,
• wherein the optical aperture device is moveable with respect to the optical element along a propagation direction of the first optical signal to change a surface area of the second optical signal impinging on the optical element