March 12, 2022
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A more elegant implementation:
Considerations-
Stray light is going to be the main issue. Wavelength dependence of collimated vs. off-angle light introduces a systematic error.
Need to rotate the axis of reflection each time, to balance out polarization effects upon reflection.
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From https://refractiveindex.info/?shelf=glass&book=BK7&page=SCHOTT
At 808 nm:
| angle (degrees) | Rp | Rs |
|---|---|---|
| 0 | 0.041365 | 0.041365 |
| 5 | 0.040948 | 0.041784 |
| 10 | 0.039693 | 0.043069 |
| 15 | 0.037593 | 0.045301 |
| 20 | 0.034640 | 0.048630 |
If angle of incidence is 10 degrees, reflected beam rotates by 20 degrees. If beam of diameter D rotates by theta, distance it must travel to not have incident and reflected overlap obeys tan(theta)=D/L so L/D=1/tan(theta)
| theta_incidence | theta_refl | L/D |
|---|---|---|
| 5 | 10 | 5.7 |
| 10 | 20 | 2.7 |
| 15 | 30 | 1.7 |
Purchases
Lambda optics 2 inch concave mirror blanks, polished both sides.
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