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.
Table 1: Technical specifications of Off-axis parabolic mirror
| 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 - |
| 7 | Surface Figure Error (for OAP surface) | ≤ λ/4 peak to valley at 633 nm measured over clear aperture，633 nm≤ λ/4 |
| 8 | Surface Quality (Scratch/Dig) | 60/40 or better |
| 11 | Laser damage threshold | ≥ 0.2 J /cm2 for ultra-short 20 -100fs pulses |
| 12 | Marking on OAP (for axis | Etched mark should be provided on the back surface of the OAP showing the geometrical centre |
| alignment purpose) | and vertex direction | |
| 13 | Vacuum compatibility | ≤ 10-5 mbar |
| 14 | Quality Assurance (QA) documents (for eachOAP) | (1) Dimension report (mechanical sizes, slant focal length, Off Axis distance and 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 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. |
| 15 | 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. |
