Vacuum UV Spectroscopy
Aberration Corrected Toroidal Holographic Grating
Specifications and Control
| - | Ultimate Specification | Standard Specification | Control |
|---|---|---|---|
| Dimension | Up to 300 mm length | - | - |
| Radius of Curvature | Down to 0.01% | 0.5% | Calibrated Samples |
| Slope error | Down to 0.5 arcsec rms longitudinal 1 arcsec rms transverse | 1 arcsec rms longitudinal 5 arcsec rms transverse | Visual interferometric comparison to calibrated sample |
| Microroughness | Down to 2 Å rms | 5 Å rms | Micromap measurements |
| Substrate | Silicon Zerodur Fused Silica SiC CVD | - | - |
| Coating | Au Pt AlMgF Ni | Cr binding layer | Quartz monitoring |
| Groove Density | Optimised with JY proprietary software | Moiré Fringes (JY patent) Optical control using recording layout (JY patent) | |
| Efficiency | Groove depth and duty cycle ratio optimised with JY proprietary software | ||
| Groove Depth | +/- 5% | +/- 10% | AFM measurements |
| c/d Ratio | +/- 5% | +/- 10% | AFM measurements |
Examples of Aberration Corrected Plane Holographic Gratings
| Size mm | Optical surface mm | Slope Error arcsec rms | Max Microroughness Å rms | Coating | Substrate |
|---|---|---|---|---|---|
| 300x50x40 | 290x40 | 1 arcsec rms longitudinal 5 arcsec rms transverse | Less than 5 | Au or Pt | Silicon Zerodur Fused Silica |
| 150x30x30 | 140x20 | 1 arcsec rms longitudinal 5 arcsec rms transverse | Less than 5 | Au or Pt | Silicon Zerodur Fused Silica |
| 75x15x150 | 70x10 | 1 arcsec rms longitudinal 5 arcsec rms transverse | Less than 5 | Au or Pt | Silicon Zerodur Fused Silica |
Note: Groove density is obtained by interference of two spherical wavefronts.