For the illumination optical system and a simple experiment, it is the glass substrate of which high surface quality used for the optical element is not required. Surface accuracy and parallelism (tolerance of wedged) is the same as optical flats for a laser.
| Material | BK7 |
| Surface flatness | λ/10 |
| Clear aperture | 90% of the actual aperture, or a circle or ellipse inscribed in the rectangle of 90% dimensions |
| Surface Quality (Scratch-Dig) | 60-40 |
Circle
| Part Number | Thickness t [MM] | Parallelism | Diameter ØD [MM] | Rear surface surface accuracy |
| S-OFB-10C03-10 | 3 | <3′ | Ø10 | Grounded |
| S-OFB-10C05-10 | 5 | <3′ | Ø10 | Grounded |
| S-OFB-15C03-10 | 3 | <3′ | Ø15 | Grounded |
| S-OFB-20C03-10 | 3 | <3′ | Ø20 | Grounded |
| S-OFB-20C05-10 | 5 | <3′ | Ø20 | Grounded |
| S-OFBP-25C05-10 | 5 | <3′ | Ø25 | Polished |
| S-OFBP-25.4C05-10 | 5 | <3′ | Ø25.4 | Polished |
| S-OFBP-30C05-10 | 5 | <3′ | Ø30 | Polished |
| S-OFBP-40C06-10 | 6 | <3′ | Ø40 | Polished |
| S-OFBP-50C08-10 | 8 | <3′ | Ø50 | Polished |
Square
| Part Number | Thickness t [MM] | Parallelism | Diameter ØD [MM] | Rear surface surface accuracy |
| S-OFB-10S03-10 | 3 | <3′ | 10×10 | Grounded |
| S-OFB-15S03-10 | 3 | <3′ | 15×15 | Grounded |
| S-OFB-15S05-10 | 5 | <3′ | 15×15 | Grounded |
| S-OFB-20S03-10 | 3 | <3′ | 20×20 | Grounded |
| S-OFB-25S05-10 | 5 | <3′ | 25×25 | Grounded |
| S-OFB-30S05-10 | 5 | <3′ | 30×30 | Grounded |
| S-OFB-1015R03-10 | 3 | <3′ | 10×15 | Grounded |
| S-OFB-2535R05-10 | 5 | <3′ | 25×35 | Grounded |
Optical parallel
| Part Number | Thickness t [MM] | Parallelism | Diameter ØD [MM] | Rear surface surface accuracy |
| S-OPB-25.4C03-10-5 | 3 | <5″ | Ø25.4 | λ/10 |
| S-OPB-25.4C05-10-5 | 5 | <5″ | Ø25.4 | λ/10 |
| S-OPB-30C03-10-5 | 3 | <5″ | Ø30 | λ/10 |
| S-OPB-30C05-10-5 | 5 | <5″ | Ø30 | λ/10 |
| S-OPB-40C04-10-5 | 4 | <5″ | Ø40 | λ/10 |
| S-OPB-40C06-10-5 | 6 | <5″ | Ø40 | λ/10 |
| S-OPB-50C06-10-5 | 5 | <5″ | Ø50 | λ/10 |
| S-OPB-50C08-10-5 | 8 | <5″ | Ø50 | λ/10 |