As mentioned below, the main problem is the detector. Most detectors are Si CCD. meaning the Si is fundamentally limited to 1100nm due to bandgap. Going beyond

As mentioned below, the main problem is the detector. Most detectors are Si CCD. meaning the Si is fundamentally limited to 1100nm due to bandgap. Going beyond that means you need a different material such as InGaAs or Ge, unfortunately CCDs are not as common or are expensive for these materials. Which then gives you two choices: - an array detector, which is pricey. - a single detector such as a photodiode behind a second slit. a detector such as these https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1285 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=12... With a moving(rotating) grating, so that the wavelengths can be reached by moving the grating. The latter is quite common in lab spectrometers.