Monochromator-spectrographs MSO350


Monochromator-spectrographs MSO350 series are general-purpose spectral instruments that can be used as monochromators or spectrographs with a large flat focal field. They are completely automated spectral devices with a focal length of 350 mm and F-number of  3.8.

Model MSO3501i and model MSO3504i have astigmatism-corrected optics what makes these devices applicable in multi-channel spectroscopy.

Automated four-grating turret (model MSO3504 and model MSO3504i) provides fast switching of gratings with high repeatability of the set wavelength.

In model MSO3501 and model MSO3501i a single-position holder is used for easy manual switching of gratings.


Optical system

 Optical scheme

Cherny–Turner (astigmatism–compensated in model MSO3501i and model MSO3504i)

1 input, 2 outputs

 Wavelength range 

185 nm – 60 μm (depends on the type of grating)

 F-number (entrance)


 Focal length (output)

350 mm

 Scanning range (limited by grating rotation angle) 

0 – 1280 nm (grating 1200 l/mm)

 Stray light  

1 х 10-5 (20 nm from laser line 632.8 nm)

Focal plane

28 х 10 mm


 Horizontal magnification 


 Vertical magnification 

1.49 (for the astigmatism-compensated models MSO3501i, MSO3504i)

 Vertical spatial resolution

< 35 μm (for the astigmatism-compensated models MSO3501i, MSO3504i)


 Motor type 

Stepper, with fractional steps 




1.62 arc seconds


± 1 step

 Max. speed 

10 000 steps/s


 Number of ports 

1 input, 1 or 2 output

 Output port repeatability (automated mirror)

± 0.03 nm

 Switching time (output port)

4 s

Optics (for grating 1200 l/mm, slit width 15 µm, wavelength 546 nm)

 Reciprocal linear dispersion 

2.37 nm/mm

 Spectral resolution:  
  • PMT (slit width 10 µm)

0.06 nm

  • Digital cameras (12 µm pixel)

0.07 nm

 Wavelength repeatability

± 0.03 nm

 Wavelength accuracy

± 0.06 nm

 Average scanning step

0.01 nm



70 х 70 х 10 mm


About the center of the grating working surface

 Grating repeatability for the automated 4-grating turret (models MSO3504, MSO3504i)  
  • wavelength

± 0,03 nm

  • vertical image

± 50 μm

 Holder for 1 manually changeable grating (models MSO3501 and MSO3501i)  
  • wavelength

± 0.05 nm

  • vertical image

± 75 µm



On-board CPU



 External interface


Dimensions and weight

 Overall sizes (LхWхH)

510 х 395 х 200 mm


19 kg (may differ, depends on configuration)

All characteristics were measured for grating 1200 l/mm, slit width 15µm, wavelength 546 nm.
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