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Description of this part for the microscope.

microscopes

Lomo microscope compensating slider:
Factory marking: СЛ1/4λ
Crystal material: Mica
Optical retardation: 1/4 lambda (approx. 140 nm)
Orientation of optical axes: diagonal, 45 degrees relative to the slider body edge

Dimensions:
Total length: 80 mm
Insertion length: 60 mm
Width: 19 mm
Height: 7,5 mm

Quarter-wave compensating slider (quarter-wave plate) introducing a phase shift of 1/4 wavelength. Used for standard compensation, determination of the optical sign of minerals, and analysis of elliptically polarized light.

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.

Description of this part for the microscope.

erpendicular/parallel axis - for Lomo Polam polarizing microscopes

Lomo microscope compensating slider:
Factory marking: СЛ1/4λ (Latin alphabet transcription: SL1/4lambda)
Alternative name: Sénarmont, CP-QS (Compensating Plate, Quarter-wave Sénarmont)
Crystal material: Mica
Optical retardation: 1/4 lambda (approx. 140 nm)
Orientation of optical axes: perpendicular and parallel to the slider body edge

Dimensions:
Total length: 80 mm
Insertion length: 60 mm
Width: 19 mm
Height: 7,5 mm

Quarter-wave compensating slider of the Sénarmont type (Sénarmont quarter-wave plate) introducing a phase shift of 1/4 wavelength. Unlike the standard quarter-wave plate, 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. Used for precise quantitative measurements of optical retardation, determination of the optical sign of minerals, and analysis of elliptically polarized light - in combination with a rotating analyzer and an interference filter (typically 546 nm or 551 nm).

The axes of the fast ray (Np) and slow ray (Ng) are oriented parallel and perpendicular to the edges of the slider body. This arrangement is used in specific types of LOMO microscope heads or with a non-standard (rotated by 45 degrees) polarizer setup, in order to achieve the correct interference effect.

A first variant of this slider is also available - standard quarter-wave plate СЛ1/4λ (Latin alphabet transcription: SL1/4lambda) with diagonal axis (45 degrees), suitable for the vast majority of classic polarizing microscopes with a standard accessory slot. 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.

Description of this part for the microscope.

КВ.КР.1 (Latin alphabet transcription: KV.KR.1)
Crystal material: Quartz
Optical retardation: 1 lambda (approx. 550 nm)
Orientation of optical axes: perpendicular and parallel to the slider body edge

Dimensions:
Total length: 80 mm
Insertion length: 60 mm
Width: 19 mm
Height: 7,5 mm

Full-wave compensating slider (gypsum plate / first-order red plate) introducing a phase shift of one full wavelength. It produces the sensitive interference tint - the purplish-red of the first order - against which even minimal changes in the birefringence of the observed specimen become clearly visible as a shift toward blue or yellow tones. Used for identification of low-birefringence minerals and for determining the sign of elongation of crystals.

Description of this part for the microscope.

marking: none (variable retardation)
Crystal material: Quartz
Optical retardation: continuously variable, from 1st to 4th order of the interference spectrum
Orientation of optical axes: aligned with the insertion direction (retardation increases with insertion depth)

Dimensions:
Total length: 115 mm
Insertion length: 78 mm
Width: 19 mm

Compensating slider in the form of a quartz wedge with variable, increasing optical retardation. Allows precise, continuous adjustment of the compensation value by sliding the wedge within the microscope accessory slot. Used for accurate determination of the interference color order of observed specimens and for precise measurement of crystal birefringence.

Description of this part for the microscope.

ameters:
Manufacturer: Lomo
Model: PLAN 25x0.50 P
Original designation: ЛОМО ПЛАН 25х0,50 П
Magnification: 25x
Numerical aperture N.A.: 0.50
Tube length: 160 mm
Cover glass: yes, 0.17 mm thickness
Immersion oil: no – this is a dry objective
Focal length: 45 mm
Thread type: RMS
Additional designation: P (Cyrillic: П) indicates that this objective is designed for use with polarized light
Special features: built-in iris diaphragm
Year of manufacture: 1976

This objective has a standard RMS thread and TL=160 mm, which means it can be used with the vast majority of microscopes from virtually any manufacturer, including Olympus, Zeiss, Nikon, PZO, Carl Zeiss Jena, Reichert, Wild and many others.

The built-in iris diaphragm allows, among other things, precise centering of the objective, because in a polarizing microscope the following diaphragms may operate simultaneously:
- field diaphragm in the illuminator
- aperture diaphragm (or two aperture diaphragms) in the condenser
- iris diaphragm in the microscope objective
- iris diaphragm in the eyepiece head
and accurate centering of all of them relative to each other is very important in polarized-light observations.

Objectives marked "P" / "Pol" feature a special construction in which the lenses are mounted and cemented in a way that prevents mechanical stress. They can be used both for conventional brightfield microscopy and for observations in polarized light.