Equations and corresponding legends for each of our EO Tech Tools.
Focal Length

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)
| ΦOS | Power of Surface 1 |
| ΦIS | Power of Surface 2 |
| Φ | Lens Power |
| nOS | Object Space Index |
| nL | Lens Index |
| nIS | Image Space Index |
| R1 | Radius of Surface 1 |
| R2 | Radius of Surface 2 |
| CT | Center Thickness |
| P | Primary Principle Point |
| P' | Secondary Principle Point |
| EFL | Effective Focal Length |
| BFL | Back Focal Length |
| FFL | Front Focal Length |
| NPS | Nodal Point Shift |
| fF | Front Focal Point |
| fR | Rear Focal Point |
Gaussian Beam

(12)

(13)

(14)

(15)

(16)

(17)
| λ | Wavelength |
| zR | Rayleigh Range |
| z | Axial Distance |
| ω(z) | Half Beam Diameter |
| ω0 | Beam Waist |
| b | Confocal Parameter |
| ωR | Rayleigh Half Diameter |
| R(z) | Radius of Curvature |
| θ | Half Angle Divergence |
Koehler Illumination

(18)

(19)

(20)

(21)

(22)

(23)

(24)
| d1 | Source to Lens 1 Distance |
| d2 | Lens 1 to Lens 2 Distance |
| d3 | Lens 2 to Spot Diameter Distance |
| DL1 | Diameter of Lens 1 |
| DL2 | Diameter of Lens 2 |
| FL1 | Focal Length of Lens 1 |
| FL2 | Focal Length of Lens 2 |
| Dsource | Source Diameter |
| Dspot | Spot Diameter |
| NAinput | Input Numerical Aperture |
| NAoutput | Output Numerical Aperture |
Laser Spot Size

(25)
| DI | Input Beam Diameter |
| DO | Output Beam Diameter |
| θI | Beam Divergence |
| L | Working Distance |
1951 USAF

(26)
SAG

(27)
| R | Radius of Curvature |
| D | Diameter |
Simply Magnifier

(28)

(29)
| MP | Magnifying Power |
| FL | Focal Length |

