• TMc150 150mm focal length compact monochromator

At just 20x11cm the TMc150 monochromator features an ultra-compact design with a single entrance and exit slit with up to two diffraction gratings, ideal for accommodation into the smallest of spaces available, particularly suitable in OEM applications.

The TMC150 is ideally suited to measurements whereby a lower spectral resolution is required, i.e. as tuneable light source, however is equally at home at the heart of a larger measurement system.

Core benefits


  • High degree of configurational flexibility
  • Wide spectral range covered in a single scan
  • 150mm focal length single monochromator
  • Czerny-Turner configuration
  • Accommodates up to two diffraction gratings
  • Single entrance and single exit slit

Optical Layout

Configuration Symmetrical Czerny Turner
Focal length 150mm
Grating mount Dual grating turret
Number of gratings 1-2
Grating size 30 x 30mm
Aperture ratio f/4.2
Number of entrance/ exit ports 1 entrance, 1 exit


Mechanical resolution drive 0.000072°/ step
Slit type Fixed, micrometer or motorised variable
Slit width & height 10µm-10mm (W) x 20mm (H)
Filter size 25mm diameter

Optical Performance (quoted for 1200 g/mm gratings)

Spectral range Within range 200nm-50µm
Linear dispersion 5.4 nm/mm
Wavelength accuracy ± 0.3nm
Wavelength reproducibility ± 0.01nm
Resolution full/reduced slit height 0.3/ 0.2nm
Stray light rejection at 2.5 FWHM 10-5


Computer interface USB 2.0
Software control BenWin+/SDK

Electrical/ Mechanical

Overall dimensions 137L x 232W x 168H mm
Optical height 110mm
Power supply External DC PSU


Diffraction gratings See Configurations Tab
Order sorting filters See Configurations Tab
Filter wheel 6-position order-sorting filter wheel (filter diameter 23mm)

Monochromator Configurations

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 TMc150.

Grating Line density (g/mm) Grating type & Blaze wavelength Maximum wavelength range (nm)
GA-G1524R0U25 2400 Plane ruled, 250nm blaze 200-600
GA-G1524H0U25 2400 Plane holographic, 250nm blaze 200-600
GA-G1524H0U3 2400 Plane ruled, 300nm blaze 200-600
GA-G1518H0U25 1800 Plane holographic, 250nm blaze 250-900
GA-G1518R0U4 1800 Plane ruled, 400nm blaze 250-900
GA-G1518R0U5 1800 Plane ruled, 500nm blaze 250-900
GA-G1512H0U25 1200 Plane holographic, 250nm blaze 300-1,200
GA-G1512R0U4 1200 Plane ruled, 400nm blaze 300-1,200
GA-G1512R0U5 1200 Plane ruled, 500nm blaze 300-1,200
GA-G1512R0U75 1200 Plane ruled, 750nm blaze 300-1,200
GA-G1512R0U9 1200 Plane ruled, 900nm blaze 300-1,200
GA-G1512R1U0 1200 Plane ruled, 1µm blaze 300-1,200
GA-G15083R1U2 830 Plane ruled, 1µm blaze 600-1,800
GA-G1506R1U0 600 Plane ruled, 1µm blaze 800-2,500
GA-G1506R1U25 600 Plane ruled, 1.25µm blaze 800-2,500
GA-G1506R1U6 600 Plane ruled, 1.6µm blaze 800-2,500
GA-G1506R1U9 600 Plane ruled, 1.9µm blaze 800-2,500
GA-G1506R2U16 600 Plane ruled, 2.16µm blaze 800-2,500
GA-G1504R1U6 400 Plane ruled, 1.6µm blaze 1,000-3,000
GA-G1503R3U0 300 Plane ruled, 3µm blaze 1,500-5,500
GA-G1503R4U0 300 Plane ruled, 4µm blaze 1,500-5,500
GA-G15015R4U0-AU 150 Plane ruled, 4µm blaze. Gold coated. 3,000-10,000
GA-G15015R6U0-AU 150 Plane ruled, 6µm blaze. Gold coated. 3,000-10,000
GA-G1501R9U0-AU 100 Plane ruled, 9µm blaze. Gold coated. 4,500-16,000
GA-G150075R10U0-AU 75 Plane ruled, 10µm blaze. Gold coated. 6,000-22,000
GA-G150075R12U0-AU 75 Plane ruled, 12µm blaze. Gold coated. 6,000-22,000
GA-G15005R18U0-AU 50 Plane ruled, 18µm blaze. Gold coated. 9,000-30,000
GA-G15005R19U5-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

TMc150 single monochromator front dimensions
TMc150 monochromator profile - Front profile
TMc150 single monochromator side dimensions
TMc150 monochromator profile - Side profile
TMc150 single monochromator top dimensions
TMc150 monochromator profile - Top profile

Software Control

The TMC150 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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