Diffraction GratingsConcaved Blazed Holographic Gratings

Concave Blazed Holographic Gratings

Concaved Blazed Holographic Gratings

A concave grating has the advantage of setting up a spectroscopic system without any imaging optics like concave mirrors. For this reason, the concave grating is used in a wide range of applications, such as analytical instruments, optical communications, biotechnology, and medical instruments. Spectroscopes incorporating concave gratings are classified roughly into two categories: polychromators or monochromators. Shimadzu offers concave gratings for applications in (1)flat-field polychromators and (2)constant deviation monochromators.

Features

  1. As a concave grating itself has the aberration correction function, it is possible to design a compact spectroscopic system by a concave grating in higher resolution than by a mechanically ruled grating.
  2. Concave gratings with small radius of curvatures are available. It is also possible to make concave gratings with high aperture ratios for fluorescence analysis and optical communication applications.
  3. All the concave gratings for flat-field polychromators and constant deviation monochromators are aberration corrected by the optimum exposure method of Shimadzu's Aspherical Wave Exposure Technology and have excellent imaging performance.
  4. The grating grooves are formed by a holographic exposure method which applies two-laser-light interference. This holographic method ensures that the stray light ,due to periodical errors of grooves, of concave gratings is much smaller than that of mechanically ruled gratings.
  5. Blaze angle is formed by an ion-beam etching technology which easily makes blazed holographic gratings with various blaze angles (blaze wavelengths).
  6. High groove density and high resolution gratings can be manufactured easily and at competitive price.
  • RoHS* compliant products.
  • *RoHS:Directive 2002/95/EC on the Restriction of the Use of certain Hazardous Substances in Electrical and Electronic
Configuration of Concave GratingsFig.3 Shape of Concave Gratings

Standard Specifications

Grating Type Unequally spaced curved-groove replica grating *1
Blank material Soda glass
Dimensional tolerances
Width(W) and hegiht (H) of rectangular blanks
Diameter(Φ) of round blanks
Thickness(T)

±0.2mm
0/-0.2mm
±0.5mm
Effective area Total area less a 2mm strip around the perimeter
Groove density tolerance (at center of grating) ±2 grooves/mm
Coating (vacuum evaporation) Aluminum (Aℓ)
Scratches and digs 80-50 (in accordance with MIL-O-13830A)
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  • *1 The grating grooves are formed with resin.
    In the interests of product improvement, the external appearance and specifications are subject to change without notice.

Be sure to prevent condensation as this can cause a significant dete rioration of optical characteristics.

Special Specifications

  1. When you need special concave gratings other than our standard, please contact us or let us know by the following Request Form.
  2. Holographic gratings (HG) are also available.