0.1 mm tomicrometer

Thorlabs' Ø1/2" and Ø1" Calcium Fluoride (CaF2) Plano-Concave Lenses offer high transmission from 0.18 µm to 8.0 μm. CaF2 is commonly used for applications requiring high transmission in the infrared and ultraviolet spectral ranges. Its extremely high laser damage threshold makes it useful for use with excimer lasers. The material exhibits a low refractive index, varying from 1.35 to 1.51 within its usage range of 180 nm to 8.0 μm. Calcium fluoride is also fairly chemically inert and offers superior hardness compared to its barium fluoride, magnesium fluoride, and lithium fluoride cousins.

Measurement of microscopic objects requires the use of an eyepiece micrometer (reticle) and a stage micrometer. The eyepiece micrometer is a round glass disk on which a scale has been etched. The eyepiece micrometer is inserted into one eyepiece and held in place in the correct focal plane of the eyepiece with a small retaining ring. The eyepiece and eyepiece micrometer can be rotated 360 degrees in the eyetube so the measuring scale can be aligned with or superimposed over the image of your specimen. A typical eyepiece micrometer would be a 5mm or 10mm linear scale featuring 50 or 100 divisions. Before using the eyepiece micrometer it is necessary to calibrate the eyepiece micrometer using a stage micrometer. A stage micrometer is simply a microscope slide with a known dimension etched upon its surface. The stage micrometer is placed directly on the stage of the microscope and brought into focus. By rotating the eyepiece both scales can be positioned parallel to each other. To calibrate the eyepiece micrometer you must first find out how many intervals of the eyepiece micrometer correspond to a certain distance on the stage micrometer. You can then calculate the value of one interval of the eyepiece micrometer. Each microscope objective must be calibrated independently.

0.01 mm tomicrometer

Thorlabs' retaining rings are used to secure unmounted optics within lens tubes or optic mounts. These rings are secured in position using a compatible spanner wrench. For flat or low-curvature optics, standard retaining rings manufactured from anodized aluminum are available from Ø5 mm to Ø4". For high-curvature optics, extra-thick retaining rings are available in Ø1/2", Ø1", and Ø2" sizes.

Mm toMicrometerto nanometer

MA285: Glass Stage MicrometerMA285 1mm divided into 100 units Stage Micrometer measurement of microscopic objects requires the use of an eyepiece micrometer (reticle) and a stage micrometer. The eyepiece micrometer is a round glass disk on which a scale has been etched. The eyepiece micrometer is inserted into one eyepiece and held in place in the correct focal plane of the eyepiece with a small retaining ring. The eyepiece and eyepiece micrometer can be rotated 360 degrees in the eyetube so the measuring scale can be aligned with or superimposed over the image of your specimen. A typical eyepiece micrometer would be a 5mm or 10mm linear scale featuring 50 or 100 divisions. Before using the eyepiece micrometer it is necessary to calibrate the eyepiece micrometer using a stage micrometer. A stage micrometer is simply a microscope slide with a known dimension etched upon its surface. The stage micrometer is placed directly on the stage of the microscope and brought into focus. By rotating the eyepiece both scales can be positioned parallel to each other. To calibrate the eyepiece micrometer you must first find out how many intervals of the eyepiece micrometer correspond to a certain distance on the stage micrometer. You can then calculate the value of one interval of the eyepiece micrometer. Each microscope objective must be calibrated independently. CALIBRATION NOTES: Length Measurement Using the Light Microscopes

Example: Each division of the metric stage micrometer is 0.01mm or 10μ. The eyepiece micrometer is divided into 100 units. First determine how many divisions of the eyepiece micrometer correspond to a certain distance on the stage micrometer and calculate the length which corresponds to one division of the eyepiece micrometer. In this example 30 divisions of the eyepiece micrometer corresponds to 20 divisions of the stage micrometer. Each division of the stage micrometer equals 10μ so 20 divisions of the stage micrometer would equal 200μ. To calculate the value of one division of the eyepiece micrometer we would divide 200μ by 30 and the result would be 6.67μ per division. The micrometer value, in this case 6.67μ, would apply only to the objective for which the calibration was made. Each microscope objective must be calibrated independently.

The table below gives the approximate theoretical transmission of these uncoated optics for a few select wavelengths in the 0.18 - 8.0 μm range. To see an excel file that lists all measured transmission values for this wavelength range, please click here.

Like all plano-concave lenses, these lenses have negative focal lengths and can be used to diverge collimated beams; in this case, the curved surface should face the source in order to minimize spherical aberration. In addition, they can be employed to offset the effects of spherical aberration caused by other lenses in an optical system.

Micrometersymbol

Extra-thick retaining rings offer several features that aid in mounting high-curvature optics such as aspheric lenses, short-focal-length plano-convex lenses, and condenser lenses. As shown in the animation to the right, the guide flange of the spanner wrench will collide with the surface of high-curvature lenses when using a standard retaining ring, potentially scratching the optic. This contact also creates a gap between the spanner wrench and retaining ring, preventing the ring from tightening correctly. Extra-thick retaining rings provide the necessary clearance for the spanner wrench to secure the lens without coming into contact with the optic surface.

The paraxial focal length of a lens is wavelength dependent. The focal length listed below for a given lens corresponds to the value at the design wavelength (i.e., the focal length at 588 nm). Since CaF2 offers high transmission from 0.18 - 8.0 µm, users may wish to use these lenses at other popular wavelengths. Click on the icons below to view theoretically-calculated focal length shifts for wavelengths within the 0.18 - 8.0 µm range.