Yes, we can offer double-side AR coated windows on any cell made from quartz with quartz or fused silica windows. We stock windows AR coated for 780-795 nm but we can offer most any AR coating although charges for a custom coating batch may apply.
Due to the coefficient of thermal expansion of Pyrex, we do not offer Pyrex cells with AR coated windows. AR coating could be applied to the outside surfaces of the windows once cells are constructed but there are significant issues. First, the cost may be prohibitive for a small quantity of cells. Second, we would be temperature limited for baking out the cells prior to filling trying to ensure we do not damage the coating as the glass expands.
Due to the difference on coefficient of expansion, quartz or fused silica windows cannot be attached to a Pyrex cell body.
Alkali metal vapor begins to react with Pyrex and quartz/fused silica in excess of 110-120C, although the reaction with Pyrex is slower. The higher the temperature, the faster the reaction until all alkali metal is consumed and no vapor exists to generate a signal. Standard vapor cells should be operated at no higher than 110C to ensure a long useful lifetime.
Paraffin inside cells breaks down with too much heat. We recommend a maximum working temperature of 80C for cells with paraffin coating. OTS coating can withstand much higher temperatures up to 200C. However, please note prolonged contact between alkali vapor and OTS coating will cause the OTS to break down. Thus, we advise customers to collect the alkali material into the cold finger at the center of the cell (fill stem) when the cells are not in use.
At this time, the process of fusing Pyrex windows to a Pyrex cell body makes attachment of wedged windows very difficult and can cause a high level of distortion and damage to the clear aperture of the windows. However, we can attach Pyrex windows at an angle with no issue.
The process of placing alkali metal vapor into a cell is done on a manifold under vacuum through a glass fill stem. The cells are then closed leaving a small tip off. Because the resulting tip off can vary with each cell there is no accurate way to tare or weigh the cells prior to filling and determine a quantity of metal inside each cell. We estimate 5-10 mg of alkali material per cell. A “heavy” fill or large quantity of alkali material can be placed inside the cell upon request. Additional charges may apply for isotopically enriched materials.
Yes, every cell we produce is He leak checked down to 1E-9 CC/sec.