• TMS300 single monochromator

Within the TMS300, up to three gratings are mounted on a turret which can be rotated through 360° allowing software selection of grating type and position. A selection of large rectangular gratings enhances light throughput whilst optical layout minimises the impact of scattered light.

Core benefits


  • 300mm focal length single monochromator in Czerny-Turner configuration
  • Configured over ranges 200nm-50µm and below 300nm
  • Accommodates up to three diffraction gratings to permitting single–scan measurement over broad spectral range
  • Up to two entrance and/or exit ports with automated mirror-based port selection for use of multiple input/ output/ detector configurations
  • Internal motorised entrance and exit slits
  • Also available as a double monochromator with additive dispersion

Optical Layout

Configuration Symmetrical Czerny Turner
Focal length 300mm
Grating mount Triple grating turret
Number of gratings 1-3
Grating size 68 x 84mm
Aperture ratio f/4.1 (at all grating angles)
Number of entrance/ exit ports 1/2 or 2/1


Mechanical resolution drive 0.00072°/ step
Slit type Internal motorised variable
Slit width & height 10µm-10mm (W) x 20 (H)
Filter size 6-position filter wheel
Filter diameter 25mm (see separate Order Sorting Filter datasheet for full range)

Optical Performance (quoted for 1200 g/mm gratings)

Spectral range Within range 200nm-50µm
Linear dispersion 2.7nm/mm
Wavelength accuracy ± 0.2nm
Wavelength reproducibility ± 0.05nm
Resolution full/reduced slit height 0.3/0.1nm
Stray light rejection at 2.5 FWHM 10-5
Wavelength acquisition speed 1000nm/s


Computer interface USB 2.0
Software control BenWin+/SDK

Electrical/ Mechanical

Overall dimensions 328L x 375W x 263H mm
Optical height 178mm
Weight Approx. 15kg
Power supply Mains input 110/220V 50/60Hz


Diffraction gratings See Configurations Tab
Order sorting filters See Configurations Tab
Filter wheel 252-6 (6-position filter wheel, includes shutter)

Diffraction Gratings

A range of gratings are available depending on the spectral range of consideration, with up to three diffraction gratings mounted to the turret of the TMS300.

Grating Line density (g/mm) Grating type & Blaze wavelength Maximum wavelength range (nm)
GA-T324R0U25 2400 Plane ruled, 250nm blaze 200-600
GA-T324H0U25 2400 Plane holographic, 250nm blaze 200-600
GA-T324H0U3 2400 Plane ruled, 300nm blaze 200-600
GA-T318H0U25 1800 Plane holographic, 250nm blaze 250-900
GA-T318R0U4 1800 Plane ruled, 400nm blaze 250-900
GA-T318R0U5 1800 Plane ruled, 500nm blaze 250-900
GA-T312H0U25 1200 Plane holographic, 250nm blaze 300-1,200
GA-T312R0U4 1200 Plane ruled, 400nm blaze 300-1,200
GA-T312R0U5 1200 Plane ruled, 500nm blaze 300-1,200
GA-T312R0U75 1200 Plane ruled, 750nm blaze 300-1,200
GA-T312R0U9 1200 Plane ruled, 900nm blaze 300-1,200
GA-T312R1U0 1200 Plane ruled, 1µm blaze 300-1,200
GA-T3083R1U2 830 Plane ruled, 1.2µm blaze 600-1,800
GA-T306R1U0 600 Plane ruled, 1µm blaze 800-2,500
GA-T306R1U25 600 Plane ruled, 1.25µm blaze 800-2,500
GA-T306R1U6 600 Plane ruled, 1.6µm blaze 800-2,500
GA-T306R1U9 600 Plane ruled, 1.9µm blaze 800-2,500
GA-T306R2U16 600 Plane ruled, 2.16µm blaze 800-2,500
GA-T304R1U6 400 Plane ruled, 1.6µm blaze 1,000-3,000
GA-T303R3U0 300 Plane ruled, 3µm blaze 1,500-5,500
GA-T303R4U0 300 Plane ruled, 4µm blaze 1,500-5,500
GA-T3015R4U0-AU 150 Plane ruled, 4µm blaze. Gold coated. 3,000-10,000
GA-T3015R6U0-AU 150 Plane ruled, 6µm blaze. Gold coated. 3,000-10,000
GA-T301R9U0-AU 100 Plane ruled, 9µm blaze. Gold coated. 4,500-16,000
GA-T30075R10U0-AU 75 Plane ruled, 10µm blaze. Gold coated. 6,000-20,000
GA-T30075R12U0-AU 75 Plane ruled, 12µm blaze. Gold coated. 6,000-20,000
GA-T3005R18U0-AU 50 Plane ruled, 18µm blaze. Gold coated. 9,000-30,000
GA-T3005R19U5-AU 50 Plane ruled, 19.5µm blaze. Gold coated. 9,000-30,000


Slit type Features
Fixed slits (FSS) - Manually controlled
- Spring leaf to ensure the correct placement of the slit
Micrometer variable slits (VSS) - Manually controlled
- Bi-lateral slits
- Variable from 10µm to 10mm
Motorised variable slits (MVSS) - PC control via USB
- Driven via internal monochromator electronics or external MAC electronics bin
- Comprising stepping motor driven bi-lateral slits
- Variable from 10µm to 10mm


An order sorting filter wheel is located inside the entrance port of the monochromator, fitted with 6 filters selected for the spectral range of use.

When measuring below 400nm, no filters are required as the corresponding wavelength of the subsequent diffraction order is less than 200nm, which is naturally blocked by the atmosphere.

Spectral range Required OS filter
<400 m None
400-700nm OS400
700-1250nm OS700
1250-2000nm OS1250
2000-3600nm OS2000
3.6-6 µm OS3600
6-10.5 µm OS6000
10.5-21 µm OS10500
> 21µm Please consult.

Further Options

ND/ BP filters Neutral density filters, used to attenuate optical signal level or band pass filters, to improve monochromator stray light performance, may be mounted in the filter wheel.
Purge ports Purge ports fitted to monochromator to allow purging with nitrogen to remove atmospheric absorbants which absorb in the UV (<200nm) and IR (Various absorption bands).
Toroidal mirrors Toroidal mirrors spherical mirrors replaced with toroidal mirrors for imaging applications.
Turret-mirror A mirror may be fitted on a free location on the turret for the purposes of relating un-diffracted light to the exit port.
418-INT 418 optical chopper mounted behind the entrance slit.
Interchangeable turrets For applications where very wide spectral range or regional optimisation is required, an interchangeable turret is available allowing the exchange of groups of three diffraction gratings to cover different spectral regions. In this case, the stepping motor in this case drives a platform to which is attached the grating assembly.
Shutter Solenoid-based shutter for timed exposure applications.

Monochromator Dimensions

TMs300 single monochromator side dimensions
TMs300 monochromator profile - Side profile
TMs300 single monochromator top dimensions
TMs300 monochromator profile - Top profile

Software Control

The TMS300 may be controlled by PC, facilitated via a USB 2.0 interface by Bentham’s Benwin+ spectroradiometer software, responsible for:

  • Accessing grating filter wheel and slit properties
  • Identifying grating type and position
  • Wavelength selection and calibration
  • Spectral measurements
  • System calibration
  • Configuration files syntax

Alternatively, Bentham offers a comprehensive SDK for user-written programs, available across a wide range of platforms (LabVIEW, Matlab, C++, SPCI protocol, etc.).

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