More about part: Lomo Polam L-213 polarizing microscope СЛ1/4λ mica quarter-wave compensating slider w. diagonal axis | SL 1/4 lambda plate 45 degrees (ID: 99532)

The axes of the fast ray (Np) and slow ray (Ng) are oriented at 45 degrees relative to the longitudinal axis of the slider. This is the standard configuration used in the vast majority of classic polarizing microscopes, where the accessory slot is parallel to the microscope arm and the vibration axes of the crystal must align precisely with the diagonal of the polarizer and analyzer directions.

A second variant of this slider is also available - of the Sénarmont type, designated by the abbreviation CP-QS (Compensating Plate, Quarter-wave Sénarmont). In the Sénarmont configuration, the crystal axis (Ng) runs parallel to the vibration direction of the polarizer, and the 45-degree effect is enforced by the microscope accessory slot - not by the orientation of the crystal within the body. The Sénarmont variant is intended for specialized LOMO microscope heads with a 45-degree-rotated accessory slot and for precise quantitative measurements of optical retardation in combination with a rotating analyzer and an interference filter (typically 546 nm or 551 nm). Before purchasing, please check the design of your microscope. Using the incorrect variant will cause the crystal axes to misalign with the vibration direction of the polarized light, preventing proper background extinction as well as precise measurements and conoscopic observations.