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TMc150 Single Monochromator

  • 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

ConfigurationSymmetrical Czerny Turner
Focal length150mm
Grating mountDual grating turret
Number of gratings1-2
Grating size30 x 30mm
Aperture ratiof/4.2
Number of entrance/ exit ports1 entrance, 1 exit


Mechanical resolution drive0.000072°/ step
Slit typeFixed, micrometer or motorised variable
Slit width & height10µm-10mm (W) x 20mm (H)
Filter size25mm diameter

Optical Performance (quoted for 1200 g/mm gratings)

Spectral rangeWithin range 200nm-50µm
Linear dispersion5.4 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 FWHM10-5


Computer interfaceUSB 2.0
Software controlBenWin+/SDK

Electrical/ Mechanical

Overall dimensions137L x 232W x 168H mm
Optical height110mm
Power supplyExternal DC PSU


Diffraction gratingsSee Configurations Tab
Order sorting filtersSee Configurations Tab
Filter wheel6-position order-sorting filter wheel (filter diameter 23mm)

Monochromator Configurations

TMc150 Configuration 

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.

GratingLine density (g/mm)Grating type & Blaze wavelengthMaximum wavelength range (nm)
GA-G1524R0U252400Plane ruled, 250nm blaze200-600
GA-G1524H0U252400Plane holographic, 250nm blaze200-600
GA-G1524H0U32400Plane ruled, 300nm blaze200-600
GA-G1518H0U251800Plane holographic, 250nm blaze250-900
GA-G1518R0U41800Plane ruled, 400nm blaze250-900
GA-G1518R0U51800Plane ruled, 500nm blaze250-900
GA-G1512H0U251200Plane holographic, 250nm blaze300-1,200
GA-G1512R0U41200Plane ruled, 400nm blaze300-1,200
GA-G1512R0U51200Plane ruled, 500nm blaze300-1,200
GA-G1512R0U751200Plane ruled, 750nm blaze300-1,200
GA-G1512R0U91200Plane ruled, 900nm blaze300-1,200
GA-G1512R1U01200Plane ruled, 1µm blaze300-1,200
GA-G15083R1U2830Plane ruled, 1µm blaze600-1,800
GA-G1506R1U0600Plane ruled, 1µm blaze800-2,500
GA-G1506R1U25600Plane ruled, 1.25µm blaze800-2,500
GA-G1506R1U6600Plane ruled, 1.6µm blaze800-2,500
GA-G1506R1U9600Plane ruled, 1.9µm blaze800-2,500
GA-G1506R2U16600Plane ruled, 2.16µm blaze800-2,500
GA-G1504R1U6400Plane ruled, 1.6µm blaze1,000-3,000
GA-G1503R3U0300Plane ruled, 3µm blaze1,500-5,500
GA-G1503R4U0300Plane ruled, 4µm blaze1,500-5,500
GA-G15015R4U0-AU150Plane ruled, 4µm blaze. Gold coated.3,000-10,000
GA-G15015R6U0-AU150Plane ruled, 6µm blaze. Gold coated.3,000-10,000
GA-G1501R9U0-AU100Plane ruled, 9µm blaze. Gold coated.4,500-16,000
GA-G150075R10U0-AU75Plane ruled, 10µm blaze. Gold coated.6,000-22,000
GA-G150075R12U0-AU75Plane ruled, 12µm blaze. Gold coated.6,000-22,000
GA-G15005R18U0-AU50Plane ruled, 18µm blaze. Gold coated.9,000-30,000
GA-G15005R19U5-AU50Plane ruled, 19.5µm blaze. Gold coated.9,000-30,000


Slit typeFeatures
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 rangeRequired OS filter
<400 mNone
3.6-6 µmOS3600
6-10.5 µmOS6000
10.5-21 µmOS10500
> 21µmPlease consult.

Further Options

ND/ BP filtersNeutral 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 portsPurge 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 mirrorsToroidal mirrors spherical mirrors replaced with toroidal mirrors for imaging applications.
Turret-mirrorA mirror may be fitted on a free location on the turret for the purposes of relating un-diffracted light to the exit port.
418-INT418 optical chopper mounted behind the entrance slit.
Interchangeable turretsFor 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.
ShutterSolenoid-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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