A monolithic Offner spectrometer is described herein as are various components like a diffraction grating and a slit all of which are manufactured by using a state-of-the-art diamond machining process. In one embodiment, a monolithic Offner spectrometer is directly manufactured by using a diamond machining process. In another embodiment, a monolithic Offner spectrometer is manufactured by using molds which are made by a diamond machining process. In yet another embodiment, a diffraction grating is directly manufactured by using a diamond machining process. In still yet another embodiment, a diffraction grating is manufactured by using a mold which is made by a diamond machining process. In yet another embodiment, a slit is directly manufactured by using a diamond machining process.