Practical Optics

186 5 ♦ Optical Systems for Spectral Measurements

for diffraction order m =−1. The grating is illuminated by a beam incident from

a direction ψ = 30

◦

. Find the positions of the entrance and the exit slits with

regard to the grating and calculate the width of the exit slit if the entrance slit is

0.2 mm in size.

5.23. AUV spectrometer has a concave grating of 600 lp/mm grooves and 250 mm

curvature. The entrance slit is 125 mm aside from the center of the grating. At the

output plane a CCD line detector of 1,024 pixels, 15 μm each, is positioned. The

spectrometer is aligned in such a way that a wavelength of 300 nm in the diffraction

order m =−2 is concentrated at the center of the detector array. Find:

(a) the location of the CCD array relative to