Pyrex cells are the least expensive reference cells and the Pyrex material has good optical transmission, approximately 92%, between the wavelengths 350 and 2400 nm. The Pyrex reference cell can be used in an undergraduate or graduate level laboratory environment. Pyrex material is a rugged material resistant to chipping and cracking. The cells are made with flat windows of optical quality Pyrex to give good light transmission.

The Pyrex cells are tested for optical throughput before shipping . A laser diode source and power meter is used to test the cell throughput. The output power of the laser source is measured using the power meter to establish a base line. The power is measured again with the cell in the optical path. An acceptable power level percentage through the cell is above 84%.

The fill material is also tested. A tunable laser diode is used to scan over one of the absorption peaks. The laser system is adjusted to scan over one of the absorption wavelengths for the fill material. The wavelengths for the different fill materials are; Rubidium 780nm, Cesium 852nm, Sodium 589nm and Potassium 764nm. The atomic elements have various absorption lines at different wavelengths. Our cell testing is performed at lines that are well defined and are accessible using a laser diode source. The cell absorption lines are measured using linear absorption measurement. Our Pyrex reference cells are excellent filters for this type of experiment.