A window is an optic. A core is a cylinder. An edged blank has already seen a generator. Use the right word. The allowances below are the ones this desk actually runs.
Windows
Plano-plano (or specified wedge) with inspected surfaces. Uncoated they cover roughly 0.6–16 µm; published bulk band is 0.6–21 µm, coatings cut the ends. At n = 2.403 one face returns 17.0%; two faces transmit (1−R)² ≈ 69%. AR is on request — 10.6 µm both faces, or dual-band 10.6 µm + 633 nm if a HeNe shares the path. Starting diameters people actually order: 12.7 mm and 25.4 mm, plus whatever the print says. Example SKU: KM-ZnSe-W12.7mmX3.0mm. Soft — KM Knoop 110. Gloves. Spent windows come back for disposal if you ask. A coated optical-grade window is not a laser-grade resonator optic. Coating sits on the surface; bulk absorption at 10.6 µm is the crystal.
South Korea polishing is listed to Dia 300 mm on the 2023.06 introduction. Larger finished windows are a quote, not an assumption. Max CVD envelope is Dia 800 × 30 mm T; that is plate, not a polished window in Florida stock.
Core-drilled blanks
This is the part you still have to grind, polish and coat. ZnSe chips. The allowances we run, because they are the ones that keep incoming inspection from fighting the shop:
- Diameter: +2.032 mm (0.080") over the requested size
- Thickness: ±0.254 mm (0.010")
- Edge chip: < 0.762 mm (0.030")
Laser grade and optical grade both core. The drill does not purify the plate. Pick the grade first. Density 5.27 g/cm³: weigh the core against CAD volume of the as-shipped diameter, including the +2.032 mm, or the mass will look high. Harris (SPIE, 1999) is still the right chapter for how this crystal machines — slow, wet, no shock.
Edged blanks and custom
Edged means we have already taken the core closer to a round ready for polish. Domes and non-plano shapes are custom — STEP or DXF. Water-jet profiles that are not circles belong with SMTY, not in the window bin.
If you are an optic shop, buy cores or SMTY. If you are a laser OEM who does not want to own a polisher, buy windows. Mixing those on one PO is how lead time grows a week of clarification emails. Ship-to country on every line — SDS travels with the crate.
References. KM Innovation ZnSe datasheet and 2023.06 plant introduction (polish to Dia 300 mm; max Dia 800 × 30 mm T). Shop practice: core +2.032 mm / ±0.254 mm / chip < 0.762 mm. Harris, D.C., SPIE (1999). KM Innovation SDS.