The PARISS® Micro-Spectrometer
A Comparison of Prism Versus Diffraction Grating Efficiency
Light throughput (efficiency) compared
close to 100% from ~390 to ~1000 nm.
Varies across the spectrum.
Maximum efficiency is at a single “blaze”:
High order diffraction
NONE all wavelengths are refracted to the
can present many orders
A prism is
significantly more sensitive
diffraction grating over an extended wavelength range.
Camera quantum efficiency (QE) versus spectral
The QE of a CCD camera falls at
The spectral resolution of a prism also falls at longer
However, this is a good thing!
for the loss in
the QE of the camera. The net result is enhanced light
throughput extending into the near IR exceeding that
possible with a diffraction grating
LightForm Inc, 2011
light away from the first order
spectrum at the detector.