This figure shows the measurement we made of the complement to the blaze angle.
Using a green laser pointer (wavelength of 532nm), we measured the dispersion off a CD, DVD, and a diffraction grating. Using this, we were able to calculate the number of grooves per mm on each.
| Object | Distance | Spread | Angle (deg) | Lines mm^-1 |
| CD | 24.0 in | 9.0 in | 20. | 640 |
| DVD | 24.0 in | 27.0 in | 48. | 1400 |
| Grating | 24.0 in | 3.125 in | 7.4 | 240 |
Based on the above measurements, the DVD has more than twice the number of grooves per mm as compared to a CD. Because the storage capacity goes as the area, this corresponds to ~4x the storage on a DVD, consistent with the specs on user-writable DVDs.
To measure the blaze angle of the diffraction grating we aligned the grating so the brightest (central) order reflected directly back at the laser. The measured angle of the diffraction grating is the complement of the blaze angle. Doing this, we determined the blaze angle to be ~35 deg.