The invention discloses a
spectrometer coaxial optical
system adopting a combination of two volume holographic gratings and a
prism for light splitting, relates to the field of
spectrometer light splitting systems and solves the problem that an existing off-axis-type
grating dispersion spectrum
system is large in size, difficult to
mount and adjust and low in stability. The
spectrometer coaxial optical
system comprises an
imaging lens, a slit, a collimating lens, a light splitting element, a converging lens and a CCD (
charge coupled device)
detector, the slit is positioned at an image focal point of the
imaging lens, the light splitting element comprises the volume holographic gratings which are completely identical and the
prism, the volume holographic gratings are glued on two sides of the
prism respectively, the
imaging lens images object light in the slit, the collimating lens collimates the object light to be parallel light, and the parallel light is refracted at an interface of the first volume
holographic grating and the prism to enter the prism after
diffraction light splitting through the first volume
holographic grating, totally reflected on the undersurface of the prism to reach an interface of the prism and the second volume
holographic grating and converged on the
CCD detector through the converging lens after
diffraction light splitting through the second volume holographic
grating. The spectrometer coaxial optical system is compact in structure, simple to
mount and adjust and high in
light energy utilization rate.