WM400

Double Additive/Subtractive Monochromator

The WM400 is a compact double monochromator offering enhanced functionality and low stray light. Its standout feature is the ability to operate in both additive and subtractive dispersion modes, providing versatile performance for various applications. 

Key Features:

  • Double Monochromator for Excellent Stray Light Rejection

  • Multifunctional: additive/dual dispersion & non-additive/subtractive dispersion

  • Compact & Cost-effective

  • High ThroughputА

  • The WM400 is a compact double monochromator offering enhanced functionality and low stray light performance.

    A key feature of the WM400  is its ability to operate in both additive and subtractive dispersion modes, offering versatility for various applications.

    The operation modes are easily switched using a two-position selector switch, allowing users to switch between the "Addition" and "Subtraction" modes without the need for additional alignment. This makes the WM400 a multifunctional, compact, user-friendly, and reliable instrument.

    In the Additive Dispersion Mode, the WM400 functions as a standard double additive monochromator with an effective focal length of 260 nm. It ensures extremely low stray light, thanks to its intermediate slit.

    In the Subtractive Dispersion Mode, the WM400  acts as a tunable filter with an adjustable bandpass and sharp edges. The width of the selected spectral range is set by the intermediate slit, while the central wavelength is determined by synchronously rotating two identical diffraction gratings.

    In Subtractive Dispersion mode, the beam path in the second half of the monochromator mirrors that of the first half, resulting in complete dispersion compensation and zero dispersion. As a result, the entire spectrum selected by the intermediate slit is imaged as a spatial line at the second monochromator’s output.

    The WM400 is equipped with a selection of ruled gratings to suit various applications. To ensure optimal dispersion compensation (zero dispersion), both halves of the monochromator are equipped with diffraction gratings made from the same matrix, guaranteeing precise alignment.

  • The WM400 double monochromator offers a wide range of accessories designed for efficient light collection from samples, whether located at a finite distance or at infinity, and provides light input to the monochromator both with and without an optical fiber, ensuring effective aperture matching.

    Adapters PS-2 and PS-3 are available for wide-aperture light collection from samples. PS-2 is optimized for high UV transmittance, while PS-3 can be equipped with an Edge filter to enhance flexibility.

    Cassegrain lenses are used for light collection from objects situated between 3.5 meters and infinity.

    Most Popular Accessories for the WM400:

    • Achromatic Fiber Adapter (AFA): This adapter includes two achromatic objectives and an SMA-905 connector, designed to match the optical fiber aperture with the WM400, minimizing stray light and optimizing light throughput. The AFA operates across a spectral range of 200 nm to 2000 nm.
       

    • Vertical Slit Position Support: The WM400’s entrance and exit slits are positioned at a 66° angle to the vertical. If a vertical slit position is required, the instrument can be equipped with a special support that adjusts the housing to achieve this configuration. Additionally, a support for horizontal slit positioning is also available upon request.

    • Adapters for optical fiber input 

    • Optical fibers 

    • Condensers for light input into the monochromator

    • Cassegrain lenses

Wm400 TECHNICAL FEATURES:

    • Optical scheme: Modified Czerny-Turner double monochromator supplemented with an optical matching unit providing either additive or subtractive dispersion

    • Focal length, mm:

      The first monochromator

      - Collimating mirror: 130
      - Focusing mirror: 142

      The second monochromator

      - Collimating mirror: 142

      - Focusing mirror: 130

    • Ports: 1 input, 1 output

    • Aperture ratio F/Number: 1: 4.5

    • Stray Light: 10-9

Diffraction Gratings*

Gratings*: interchangeable one pair is supplied with the instrument, other pair is an option

Number of Lines per mm 1200 600 300
Grating Size (mm) 25 x 25 x 8 25 x 25 x 8 25 x 25 x 8
Blazing Wavelength (nm) 280 600 1500
Usable Wavelength Range (nm)2) 190–650 385–1300 770–2600
Mechanical Range (nm) 0–760 0–1500 0–3000
Wavelength
Reciprocal linear dispersion (average) of the first monochromator (nm/mm) 5.8 11.6 23.2
Wavelength Accuracy (nm) ±0.15 ±0.25 ±0.5
Wavelength Repeatability (nm) ±0.05 ±0.01 ±0.2
Wavelength Step Size (nm) 0.01 0.02 0.04
Wavelength Scan Speed (nm/s) 19 38 76
Wavelength Resolution (nm) 0.07 0.14 0.28
Dispersion Addition Mode
Reciprocal Linear Dispersion (average) (nm/mm) 3.0 6.0 12.0
Width of the Selected Spectral Range (nm) 0.2–6 0.4–12 0.8–24
Dispersion Subtraction Mode
Reciprocal Linear Dispersion (nm/mm) 0 0 0
Width of the Selected Spectral Range (nm) 0.2–40 0.4–80 0.8–160
Width of 25 µm Entrance Slit Image with 2.5 mm intermediate slit (µm) 32 32 32
Width of 25 µm Entrance Slit Image with 5.0 mm intermediate slit (µm) 43 43 43
  • 1) Upon request, diffraction gratings with customized groove densities and blaze wavelength can be provided.
  • 2) The usable wavelength range includes wavelengths where the grating efficiency exceeds 30%.

  • Entrance & Exit slits: micrometric

    Silt width, mm: Adjustable from 0 to 2

    Silt height, mm: ± 12

    Parallelism: ±1

    Micrometer reading accuracy, um: ±1

    Intermediate silt: micrometric

    Silt width, mm: adjustable from 0 to 5

    Silt height, mm: ± 12

    Parallelism: ±1

    Micrometer reading accuracy, um: ±1

    • PC connection: full speed USB

    • Electrical Services Requirements:
      Single phase main 85 – 264; 47-63 Hz

    • Dimensions: 265 х 195 х 210 mm

    • Weight: 8 kg

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