Home / Custom / Optical Components / Optical Mirror / Off-Axis Parabolic (OAP) Mirror 
Scope of Supply: This indent is for procurement of "Off Axis Parabolic (OAP) Mirrors" for ultra-short high power (up to 1PW level, 25 fs,Maximum Energy 25 J) Ti: Sapphire (800 nm) laser beam focusing. The OAP mirrors shall be compatible for use in the vacuum environment (< 10-5 mbar). Necessary quality assurance (QA) test reports as per the tender specifications should be provided. The details of OAP mirror specifications are given in the following table.
Optical glass such as K9, fused silica, sapphire, MgF2, silicon (Si), ZnSe, ZnS, etc. These materials possess high transmittance, low absorption, low scattering, uniform refractive index, and specific dispersion characteristics.
Precisely hemispherical. The machining precision of the center and radius of curvature of the sphere is extremely high.
The surface is precision polished to an optical grade of 10-5 to ensure image quality and reduce scattering and aberrations.
An AR coating is typically applied to the concave surface to maximize the transmittance of specific wavelengths of light (e.g. visible light) and reduce reflection loss.
| S. No. | Parameter | Nominal value |
|---|---|---|
| 1 | Configuration | Equithick or Wedge configuration |
| 2 | Diameter (mm) | 250 mm + 0/-1 mm |
| 3 | Slant focal length (Reflected effective focal length) | 2000 ± 10 mm |
| 4 | Off axis angle (degree) | 12.5o ± 0.5o |
| 5 | Clear aperture | ≥ 230 mm |
| 6 | Material | Glass or equivalent substrate |
| 7 | Reflective Coating | High-Reflectivity, Multi-Layer Dielectric |
| 8 | Coating Reflectivity | > 98.5 % for s-pol. light |
| 9 | Spectral bandwidth support | 750 – 850 nm or wider (to be used with Ti: Sa laser operating at central wavelength at 800 nm)750 - 850 |
| 10 | Surface Figure Error (for OAP surface) | ≤ λ/4 peak to valley at 633 nm measured over clear aperture |
| 11 | Surface Quality (Scratch/Dig) | 60/40 or better |
| 12 | Laser damage threshold | ≥ 0.2 J /cm2 for ultra-short 20 -100fs pulses |
| 13 | Marking on OAP (for axis alignment purpose) | Etched mark should be provided on the back surface of the OAP showing the geometrical centre and vertex direction |
| 14 | Vacuum compatibility | ≤ 10-5 mbar |
| 15 | Quality Assurance (QA) documents (for eachOAP) | (1) Dimension report (mechanical sizes, slant focal length, Off Axis distance andangle). (2) Interferogram analysis of OAP surface after coating to assess the surface figure error over an area of at least of 100 mm in diameter or more. (3) Reflectivity curve over full wavelength range (750 nm - 850 nm orwider). The above reports should be sent to purchaser before shipment for approval. Final shipment is allowed only after approval of test reports from purchaser side. |
| 16 | Witness Sample | One witness sample (with size ≥25mm × 25 mm, or ≥diam 25mm, or of nearest standard), having identical substrate and coating shall be shipped along with OAPs at the time of delivery. The purchaser will have the discretion to independently evaluate the QA parameters and performance test on the witness sample for evaluation. |
Test and Acceptance Criteria 3.1Factory Test Reports before shipment:Following factory test reports for all OAP mirrors manufactured for supply against the purchase order shall be provided before shipment of the material:
Please quote QA test reports separately
(1) Dimension report (mechanical sizes, slant focal length, Off Axis distanceand angle)
(2) Interferogram analysis of OAP surface after coating to assess the surface figure error over an area of at least of 100 mm in diameter or more
(3) Reflectivity curve over full wavelength range (750 nm - 850 nm or wider) . The Supplier should ship the material only after approval of factory test reports from the purchaser. The witness sample shall be shipped along with OAPs at the time of delivery.
Warranty: The mirrors shall be warranted for at least three months from the date of delivery at purchaser site. Thanks
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