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2. Geometric versus Diffraction Limited Spot Diameter ApproximationsOptical Element Parameters Materials PropertiesThermal Effects/ Athermalization ApproximationsScattering ApproximationsSoftware Tools. OUTLINE. 3. For M2 > 6, use (Geometric) Spot Diameter Approximations. . RMS diameter = 0.7 Dz/Fn.
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1. 1 First-Order Opto-Mechanical Considerations in High Power Applications
2. 2
3. 3 For M2 > 6, use (Geometric) Spot Diameter Approximations
4. 4 Rules of Thumb for Opto-mechanical Tolerances When Dealing with High Power first order Opto-Mechanical Calculations, need to first look thermal effects on Radius of Curvature, Lens Thickness, and scatter effects due to surface finish calculations. These values are shown with red values.When Dealing with High Power first order Opto-Mechanical Calculations, need to first look thermal effects on Radius of Curvature, Lens Thickness, and scatter effects due to surface finish calculations. These values are shown with red values.
5. 5 Thermal Effects on a Len Thickness and Radius of Curvature
6. 6 Thermal Stress, s
7. 7 Thermo-Optic Coefficients, n, and CTE Values of Materials CTE is required to detemine Thermo-Optics Coefficients. Equation for defocus as a function of temperature on next slide.CTE is required to detemine Thermo-Optics Coefficients. Equation for defocus as a function of temperature on next slide.
8. 8 Thermal Effects Singlets or Doublets or Triplets can be calculated as a single lens, for first order thermal effects defocus.Singlets or Doublets or Triplets can be calculated as a single lens, for first order thermal effects defocus.
9. 9 Total Integrated Scatter Measurement For a static surface at a constant temperature, the back scatter can be approximated by TISb.
For a static surface at a constant temperature, the back scatter can be approximated by TISb.
10. 10 Back Scatter Approximation This will be shown in the Plastic system example. Note scaling laws for wavelengths other than l are provided in references 1a and 1b.
Equations are normalized to the specularly reflected beam (not the incident beam), so TIS can be greater than 1.
This will be shown in the Plastic system example. Note scaling laws for wavelengths other than l are provided in references 1a and 1b.
Equations are normalized to the specularly reflected beam (not the incident beam), so TIS can be greater than 1.
11. 11 U.S. Opto-mechanical design between various disciplines When first order calculations are not enough, need to use software packages as shown above.
For dynamic loads/vibration analysis – use Structures Softwares
For Circularly symmetric optics that needs to be transferred to CAD or Structures, use Zernikes polynomialsWhen first order calculations are not enough, need to use software packages as shown above.
For dynamic loads/vibration analysis – use Structures Softwares
For Circularly symmetric optics that needs to be transferred to CAD or Structures, use Zernikes polynomials
12. 12 Conclusion
13. 13 Back up Slides are slides 14 thru 17.
14. 14 Diffraction Limited Approximations
Applies to M^2 < 4 Laser Systems Zernike Polynomials don’t fit well under F-number of 1.5.
Zernike Polynomials don’t fit well under F-number of 1.5.
15. 15 Various Mounting Techniques The z or “sag of a spherical surface” is calculated using the parabolic (k = -1) or circular ( k = 0) approximation. It has many uses. One use is determining lens edge thickness. Note ai is the Zernike coefficient and Zi is the Zernike Polynomial, which is only applicable for Circular pupils.The z or “sag of a spherical surface” is calculated using the parabolic (k = -1) or circular ( k = 0) approximation. It has many uses. One use is determining lens edge thickness. Note ai is the Zernike coefficient and Zi is the Zernike Polynomial, which is only applicable for Circular pupils.
16. 16 Calculating Tilt Note f/D is the F# of the plano-convex lensNote f/D is the F# of the plano-convex lens
17. 17 Calculating the Change in Focal Length for a Plastic Singlet, f = 25 mm, 10 mm diameter. Note f/D is the F# of the plano-convex lensNote f/D is the F# of the plano-convex lens