Product

Optical and Laser Devices

Aspherical Mirrors

Off-axis Parabolic Mirrors

Off-axis Parabolic Mirrors

An off-axis parabolic mirror converts plane waves into spherical ones and vice versa with high accuracy. This aspherical mirror is indispensable for spectrometers and astronomical optical instruments which require high resolution.

When a spherical mirror is used under off-axis conditions, spherical and coma aberrations occur, which cause the degradation of resolution of a spectrometer. Off-axis parabolic mirrors theoretically eliminates these aberrations and ensures
high resolution even in a short focal length compact spectrometer.

The off-axis parabolic surface used in Shimadzu off-axis parabolic mirrors is, when expressed mathematically, a part of a rotary symmetric parabolic surface represented by Y = X2/4F (where, F: focal length, Y is the rotary symmetric axis and X is the displacement on the axis.)

Features

  • Shimadzu off-axis parabolic mirrors are replicated by master mirrors that pass through rigorous inspections such as zone, Foucault, and interference tests.

  • At the rear side of each mirror, a notch is grooved to indicate the mounting direction (points to the rotary symmetric axis).

  • Non-Use of Specific Chemical Substances*1

  • *1. RoHS Directive: Directive on the restriction of the use of certain hazardous substances (mercury, cadmium, lead, hexavalent chromium, PBB and PBDE) in the EU. (EU Directive 2010/65/EC)

Product List

Code Number*1 On-axis focal length f(mm) Off-axis focal length f'(mm) Off-axis angle
θ(°)
Width and Height (mm) Effective area FA(mm) Central thickness T(mm)
125-15-4040 125 134 15 40×40 Φ36 16
200-09-4040 200 205 9 40×40 Φ36 16
200-12-4040 200 209 12 40×40 Φ36 16
275-07-4040 275 279.1 7 40×40 Φ36 16
275-09-4040 275 281.9 9 40×40 Φ36 16
275-09-6575 275 281.9 9 65×75 Φ60 16
275-06-5555 275 277.5 5.5 55×55 Φ50 16
275-07-6060 275 279.1 7 60×60 Φ55 16
787-03-6464 787 789.2 3 64×64 Φ60 16
(*1):How to express a code number.

Specifications

Classification Replica parabolic mirror*1
Blank Material Soda glass
External Dimensional Tolerance(W,H) 0/-0.2 mm
Central Thickness Tolerance(T) ±0.2 mm
On-axis Focal Length Tolerance(f) ±0.5%
Surface Accuracy Within λ /2*2
Effective area(FA) Ref table
Coating Aluminum
Scratches & Digs 80-50(as per MIL-O-13830A)
Thermal and Humidity Conditions for Storage 0°C to 50°C,50% RH max.(no conensation)
*When temperature is from 0°C to 40°C,humidity should be 80% RH max.
(*1):Paraboloidal surface is formed by resin.
(*2):λ =632.8nm

Schematic Diagram

Schematic Outline
Applications

  • Spectrometers

  • Interferometers

  • Astronomical optical instruments

  • Spectrum analyzers

  • Beam Expander and Beam Collimator

Examples of application in spectrometers

  • Littrow-type spectrometer

Littrow-type spectrometer

  • Czerny-Turner spectrometer

Czerny-Turner spectrometer

Optional Specification

  • Off-axis parabolic mirrors with the following optional coating are available upon request
Type:
  1. Al + MgF2 (for vacuum ultraviolet)
  2. Au (for vacuum ultraviolet)
  3. Au (for infrared)
For more information, please contact us.



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