MS750 Series Monochromator-Spectrograph, Perfect Imaging

Monochromator-spectrograph MS750 series are devices with with a large flat focal field, combined with a high-intensity, accuracy and spectral resolution. They are completely automated spectral devices with focal length of 750 mm and F-number of 1/8.9, which can be used both as monochromators and spectrographs.

Description

Monochromator-spectrograph MS750 series are devices with with a large flat focal field, combined with a high-intensity, accuracy and spectral resolution. They are completely automated spectral devices with focal length of 750 mm and F-number of 1/8.9, which can be used both as monochromators and spectrographs.

High-quality optics and wide choice of diffraction gratings provide devices operation in a wide range from 185 nm up to 60 µm (depending on the selected grating).

 

M750 Series monochromator-spectrographs are based on Cherny–Turner asymmetric scheme that allows to minimize of aberrations and exclude spectra re-entrance from diffraction gratings and mirrors.

Model MS7501i and model MS7504i have the astigmatism-correctedoptics what makes these devices applicable in multi-channel spectroscopy.

Automated four-grating turret (model MS7504 and model MS7504i) provides a fast switching of gratings with high repeatability of the set wavelength and the vertical image.

 

In MS7501 and MS7501i models a single-position holder is used for easy manual switching of gratings.

A wide choice of changeable gratings gives the best combination of high energetic efficiency and maximal spectral resolution for different spectrum areas.

 

Monochromators–spectrographs of MS750 series have one input port and two output ports. Selection of an output port is realized with an automated mirror. Either output spectral slits or multi-channel detectors can be installed on each of the output ports.

Extremely high spectral resolution – better than 0.02 nm for grating 1200 grooves/mm,makeS monochromators-spectrographs of MS750 series ideal devices for high resolution spectroscopy: Raman spectroscopy, laser-induced breakdown spectroscopy and also for multi-channel spectroscopy – models MS7501i and MS7504i, which provides extremely high spatial resolution along the slit heigh.

I M A G I N G

3MS7501 site

MS benefits

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. fig2 MS 7501 optical shem

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. fig3 MS 7504 optical shem

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. book-2

Theory & Instructions
1. Spectral Instrument. Basic Concepts and Characteristics.
2. Spectral Devices. A Spectral Device Selection. 
3. Spectra Detection. Detector Selection.

 

 Monochromator-spectrograph MS750 series, models

MS7501 MS7501i MS7504 MS7504i
Diffraction unit Single-position holder for manually changeable gratings Single-position holder for manually changeable gratings Four–grating turret Four–grating turret
Optics  Standard Imaging Standard Imaging

 

In the devices with the standard optics (model MS7501 and model MS7504) a flat entrance deflecting mirror is used, and in the astigmatism–compensated devices (model MS7501i and model MS7504i) a cylindrical mirror is used as an entrance deflecting.

As well as in all Czerny–Turner design spectral devices, in the MS750 series an axis of the diffraction gratings rotation goes through the center of grating operating surface and coincides with the direction of grooves. This fact provides the stability of the geometry of the beams for formation of a flat and fixed focal field. The image quality in the whole flat focal field is optimized due to the use of an asymmetric scheme and use of a focusing large-size mirror allows one to use the whole focal field width without vignetting. Besides, Cherny–Turner asymmetric scheme provides a low level stray light and light re-entrance from the optical elements and detectors can be avoided.

In MS7504 and MS7504i the gratings rotation axes are arranged perpendicular to the spectrum scanning axis, providing a high repeatability of wavelength setting at replacing of gratings.

 

 

Specification

Optical system

Optical scheme: Cherny–Turner
(astigmatism–compensated in model MS7501i and model MS7504i)
Ports: 1 input, 2 output
Wavelength range: 185 nm – 60 µm (depends on the type of grating)
F/number (entrance): 8.9
Focal length (output): 750 mm
Scanning range limited by the grating rotation angle: 0 – 1270 nm (grating 1200 l/mm)
Main mirrors: spherical
Stray light: 5.5 х 10-7 (20 nm from laser line 632.8 nm)
Focal plane: 28 х 10 mm

Optical scheme is optimized for:

  • minimization of coma aberration over the whole operating spectral range
  • elimination of the light re-entrance from two basic mirrors
  • elimination of the light re-entrance between mirrors
    of the instrument and input windows of the detectors in the focal plane
  • a large plane focal field for the whole operating spectral range
  • astigmatism compensation for the whole operating spectral range
    by means of special correcting optics (for imaging modifications MS7504i and MS7501i)

*Imaging

*Horizontal magnification: 1.05
*Vertical magnification: 1.125
*Vertical spatial resolution: <15 m=”” –15–=””>

* Characteristics of models with astigmatism compensation: MS7501i, MS7504i

Spectral Image Enlarged Spectral Image

Spectral images obtained with imaging monochromator-spectrograph MS7504i (grating 1800 l/mm,
light source – mercury-helium lamp, pixel size of CCD detector 24×24 µm).

 Drive

Motor: microstepper
Drive: sine
Step size: 0.22 arc seconds
Precision: ± 1 step
Max. speed: 10000 steps/s

**Optics

Type of grating: 1200 l/mm,
λ = 546 nm
Echelle, 75 l/mm,
λ = 200 nm, 120 order
Reciprocal linear dispersion: 1.02 nm/mm 0.055 nm/mm
Spectral resolution:
– PMT (slit width 10 µm): 0.015 nm 0.0008 nm
– digital cameras (12 µm pixel): 0.02 nm 0.0011 nm
Repeatability: ± 0.007 nm ± 0.0009 nm
Wavelength accuracy: ± 0.034 nm ± 0.0045 nm
Average scanning step: 0.0017 nm
Scanning step at 200 nm: 2.25 x 10-4 nm

** For grating 1200 l/mm, slit width 15 µm, wavelength 546 nm

Gratings

Size: 80 х 70 х 10 mm
Rotation: About the center of grating working surface
Mounting: 1. Automated 4-grating turret (models MS7504, MS7504i)

2. Positioner for 1 manually changeable grating (модели MS7501 и MS7501i)

Grating repeatability for the automated 4-grating turret
(models MS7504, MS7504i):
– wavelength: ± 0.03 nm
– vertical image: ± 50 µm
Grating repeatability for 1 manually changeable grating (models MS7501 and MS7501i):
– wavelength: ± 0.05 nm
– vertical image: ± 75 µm

Ports

Number: 1 input, 2 output
Output port repeatability (automated mirror): ± 0.01 nm
Switching time (output port): 10 s

Spectral slits

Control: Automated (drive) or manual (micrometer)
Width: Regulated from 0 up to 2.0 mm
Parallelism: ± 1 µm
Accuracy (slit 1 mm): ± 10 µm
Repeatability: ± 1 µm (± 1.5 µm – manual slit)
Reading accuracy (micrometer): 2 µm
Step size: 0.5 µm
Height: Diaphragm-regulated from 0 up to 10 mm

Integrated shutter

Shut time: ~ 100 ms
Max. frequency: 1 Hz
Control: On-board CPU or TTL-signals from the external device

Control

Central: on-board CPU
External: PC
External interface: Ethernet

Dimensions

Overall sizes (LхWхH): 950 х 361 х 343 mm
Weight: 45 kg (may vary, depends on configuration)

 

Monochromator-spectograph MS750

 

 

Configuration

MS750 Series monochromators-spectrographs are spectral devices with big focus length, which posses a wide range of different configurations for realization of spectral tasks which requires an extra-high spectral resolution and precision.

We offer several configurations, a wide choice of diffraction gratings, a great number of accessories and two types of the software.

You have a possibility to choose a necessary device configuration depending on your task to be solved from the given below list or consult our specialists

You can choose:

  • a housing
  • a diffraction gratings assembly
  • a number of diffraction gratings, their parameters
  • a number of input ports
  • a number of output ports
  • a number and type of spectral slits
  • accessories
  • software
Housing:
  • a housing with embedded controller
  • worm mechanism of grating rotation
  • input mirror
  • basic mirrors (focusing and collimator)
  • integrated shutter

Housing options:

  • with standard aluminium (Al+MgF2) coated optics
  • with standard gold coated optics
  • with imaging (astigmatism corrected) aluminium (Al+MgF2) coated optics
  • with imaging (astigmatism corrected) gold coated optics

 

With interference optics for all options of the housing, on request

 

 

 

Housing of monochromator-spectrograph MS750

Diffraction grating assembly
 

MS750 series monochromators–spectrographs are available with two types of diffraction grating mounting:

Аutomated turret
(model MS7504 and model MS7504i)

Up to 4 gratings may be set in the turret. Use of the automated turret allows fast switch of gratings with the help of the control program. Turret axis is orthogonal to the grating rotation axis (wavelength scanning) and provides a high repeatability of the set wavelength while the gratings are switched.

 

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. 02 avtomatizir turel

Single grating holder
(model MS7501 and MS7501i)

It allows easy manual switching of gratings. A grating is positioned in a holder with high accuracy and no additional tuning of the device is needed while the grating is changed.

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. 03 derjatel na resh

Input port and entrance slit
 

The devices of this series have one input port on which an entrance spectral slit is installed.

There are two types of slits:

  • Manually operated
  • Automated

All spectral slits have standard coupling flanges providing direct attachment of various accessories of own production to the entrance slit: optical fiber adapter, condenser F#-matcher, filter wheel, fast shutters, etc.

 

 

Input port of mocnochromator-spectrograph MS750

 

Integrated shutter
 

MS750 Series devices have an integrated shutter. It is used for measuring of the background signal or dark signal of photodetector and also for protection of the detectors from high light intensities – the shutter is automatically shut while switching the gratings, filters, zero-order wavelength setting or change of the output port. The shutter can be controlled through software or via the external device TTL-signals.

 

Output ports
 

MS750 Series devices have two output ports – axial and lateral.
If you intend to select output port you should use an optional motorized Flip output mirror. Exit spectral slits а can be installed on any output port. Adapters for multi-channel detectors (CCD camera) could be installed on the lateral (upper) output port only.

MS750 monochromators-spectrographs can be provided with the following output ports:

  • one axial output port
  • one lateral output port
  • two output ports
 

Two output ports

 

One axial output port

This configuration is usually applied if only one detector is used.

In this configuration a fixed output mirror is used to direct the output radiation.

In this case the lateral port is covered with a cap.

 

 

One axial output port

 

One lateral output port

This configuration is usually employed when one multi-element detector is used, though an integral detector can also be installed on the upper output port. A fixed turning mirror which directs output radiation to the upper output port is used in this configuration. In the device configuration with one output upper port the lateral output port is closed by a blank flange.

 One lateral output port

 

Two output ports

When both output ports are used the automated output port selection mirror is installed in the device for the fast switching between the ports.

For one lateral output port a fixed flip mirror is used.

When choosing an upper output port a flip mirror is used which is being brought in the optical path and directs output radiation upwards.
A flip mirror is taken away from the optical path and the output radiation is directed to the lateral port with the help of a fixed turning mirror while selecting a lateral output port.

A high precision of the output mirror positioning (better than 0.03nm for 1200 l/mm grating) allows obtaining of reproducible spectra at switching the detectors while scanning.

 

 

Two output ports, flip mirror

 

Spectral slits
 

Monochromators-spectrographs of MS750 Series have two types of input and output spectral slits:

  • Manually operated
  • Automated (combined)

Manually operated spectral slits

width regulated from 0 up to 2.0 mm
parallellism ± 1 µm
accuracy (slit width 1 mm) ± 10 µm
repeatability ± 1.5 µm
reading accuracy (micrometer) 2 µm
height 10 mm

 

The slit width is operated manually by means of the micrometer. Slit height is regulated by a diaphragm in the range from o to 10 mm.

 

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. 09 manual slit

Automated spectral slits

width regulated from 0 up to 2.0 mm
parallelism ± 1 µm
accuracy (slit width 1 mm) ± 10 µm
repeatability ± 1 µm
reading accuracy (micrometer) 2 µm
step size 0.5 µm
height 10 mm

 

In the automated spectral slits a stepper motor is used for PC control over the blades opening width. The slit width also may be controlled manually by means of a micrometer screw. The slit height is regulated by a special diaphragm.

 

 

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. 10 avtomatizir schel

 

All spectral slits have standard flanges that make possible attachment of various accessories of own production directly to the entrance slit: optical fiber adapter, condenser F#-matcher, filter wheel, fast shutter, detectors based on photodiodes, PMT, etc.

Slit with fiber bundle adapter

 

Control of the devices
 

Monochromators-spectrographs of MS750 Series are completely automated spectral devices.

The basic control of the devices is executed through the embedded controller. It performs continuing control of commands execution from the external control device.

esides, the embedded controller takes control over the built-in ADC which processes signals from the integral photodetectors–PMT, photodiode and etc.

External control of the devices can is performed through PC.

 

DevCtrl software

The software DevCtrl is supplied with the device.

DevCtrl controls over all drivers and units of the device and accessories. The software also gives an access to the system parameters and setup coefficients of the device.

 

 

 

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. 31

Spectroscopy software SpectraSP

Spectroscopy software SpectraSP is intended for joint control over monochromators–spectrographs and detection systems based on the integral or multi-element photodetectors. SpectraSP provides simultaneous control over the device and optical radiation detection by means of various detectors with subsequent data processing and their graphical displaying.

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. po ms750
Configuration diagrams of the devices
 

Accessories for input port

Input port

 

Accessories for output ports

Output port

 

Gratings

While choosing a device configuration it is important to select properly the diffraction gratings. A right selection of the diffraction grating allows one to obtain the best combination of high energetic efficiency and spectral resolution.

The basic grating parameters which determine their right choice you can find in the methodical material “Spectral Instrument. Basic Concepts and Characteristics.”

We propose a wide range of diffraction gratings to be used in the MS750Series. Please, choose a necessary grating from the given below list, or consult our specialists.

SOL instruments: спектрометр, рамановский микроскоп, эмиссионный спектрометр. dif grating 435x315

Basic parameters for correct selection of diffraction gratings:

In the Table “Selection of diffraction gratings” groove density and blaze wavelength belong to a diffraction grating parameters. Other parameters characterize a spectral device together with a selected grating.

  • Groove density. The diffraction grating has a periodic structure. Such parameters as resolving power and free spectral range are determined by the periodic structure properties of a diffraction grating. The period of grating is the distance through which grooves are repeated. The reciprocal value of a grating period is called the groove density and displays the number of grooves in 1 mm.
  • Blaze wavelength. The reflectivity of a grating depends on the grooves geometry, because the direction to the center of the diffraction maximum is determined by the mirror reflection of the incident beam from the edge of a groove. In spite of rather flat profile of diffraction maximum a blaze wavelength that corresponds to the maximum efficiency of the grating has been adopted as a feature for convenience of calculation.
    When selecting a grating it is useful to determine a blaze wavelength for a required grating on the spectral range of limited wavelengths WL1 and WL2. The blaze wavelength is determined by the ratio:
    WLBlaze = 2 ∙ WL1 ∙ WL2 / (WL1 + WL2).
  • Reciprocal linear dispersion. The light from a grating in the focal plane of a spectral instrument forms a spectrum. Linear dispersion is used for a spectrum characteristic, which is defined as a reciprocal value of the product of angular dispersion of a grating and focal length of a spectral instrument and shows the spectral range that falls on a single linear distance in a focal plane.
  • The spectral resolution. Limiting resolution of a spectral instrument is equal to the minimum half-width of its instrument function. The instrument function is determined by finite sizes of entrance diaphragm, aberrations and also distortions caused by inaccuracy in manufacturing and adjustment of optical elements of instrument. In addition, instrument function, and thus spectral resolution are dependent on lighting method of entrance slit, used aperture and registration system parameters.
  • Operating wavelength range. Energy efficiency range referred to the wavelength region in which grating reflection coefficient is not less than  0.405 of the maximum. In the first order this range is limited by the wavelengths: ⅔ ∙ WLBlazeand 2 ∙ WLBlaze.
    Operating range usually corresponds to a grating energy efficiency. In some cases, for gratings with a high groove density and large blaze wavelength, the long-wave border of operating spectral range of instrument is limited by a maximal rotation angle of a grating which is defined by design of instrument.

 

Table for selection of diffraction gratings

Model Line density,
mm-1
Blaze wavelength, nm  *Reciprocal linear dispersion, nm/mm Spectral resolution,
nm
Operating wavelengths range, nm Spectral range limited by the grating rotation angle, nm
75 0.11
(wavelength 200 nm,
120 order)
0.0024
(wavelength 200 nm,
120 order)
783600 3600 hol 0.33** 0.0064 185 – 450 500
782422 2400 225 0.52 0.01 185 – 450 750
782427 2400 270 0.51 0.01 185 – 540 750
782770 2400 400 0.47 0.009 270 – 750 750
781827 1800 270 0.7 0.014 185 – 540 1000
781840 1800 400 0.67 0.013 270 – 800 1000
781840 1800 500 0.63 0.012 335 – 1000 1000
781875 1800 750 0.51 0.01 500 – 1800 1000
781225 1200 250 1.08 0.021 185 – 500 1500
781228 1200 280 1.07 0.021 190 – 560 1500
781240 1200 400 1.05 0.021 270 – 800 1500
781250 1200 500 1.03 0.02 335 – 1000 1500
781260 1200 600 1 0.02 400 – 1200 1500
781275 1200 750 0.95 0.019 500 – 1500 1500
780623 600 230 2.19 0.043 185 – 460 3000
780630 600 300 2.18 0.043 200 – 600 3000
780640 600 400 2.17 0.043 270 – 800 3000
780650 600 500 2.16 0.042 335 – 1000 3000
780660 600 600 2.14 0.042 400 – 1200 3000
780675 600 750 2.11 0.042 500 – 1500 3000
7804008 400 800 3.23 0.06 535 – 1600 4500
7804012 400 1200 3.16 0.06 800 – 2400 4500
7804017 400 1700 3.03 0.06 1135 – 3400 4500
7804020 400 2000 2.94 0.06 1335 – 4000 4500
7804025 400 2500 2.75 0.06 1670 – 4500 4500
780330 300 300 4.39 0.09 200 – 600 6000
780335 300 350 4.39 0.09 235 – 700 6000
780350 300 500 4.38 0.09 335 – 1000 6000
780360 300 600 4.37 0.09 400 – 1200 6000
780370 300 700 4.35 0.09 470 – 1400 6000
7803010 300 1000 4.31 0.08 670 – 2000 6000
7803015 300 1500 4.23 0.08 1000 – 3000 6000
7803020 300 2000 4.11 0.08 1335 – 4000 6000
7803030 300 3000 3.8 0.08 2000 – 6000 6000
7803035 300 3500 3.59 0.08 2330 – 7000 6000
780235 200 350 6.6 0.13 235 – 700 9000
780240 200 400 6.6 0.13 270 – 800 9000
780250 200 500 6.6 0.13 335 – 1000 9000
780270 200 700 6.6 0.13 470 – 1400 9000
7802015 200 1500 6.5 0.13 1000 – 3000 9000
7802020 200 2000 6.4 0.13 1335 – 4000 9000
7802025 200 2500 6.3 0.13 1670 – 5000 9000
7802030 200 3000 6.2 0.12 2000 – 6000 9000
781547 150 475 8.8 0.17 320 – 950 12000
781570 150 700 8.8 0.17 470 – 1400 12000
7815030 150 3000 8.5 0.17 2000 – 6000 12000
7815045 150 4500 8.1 0.16 3000 – 9000 12000
780165 100 650 13.2 0.26 435 – 1300 18000
780170 100 700 13.2 0.26 470 – 1400 18000
7801010 100 1000 13.2 0.26 670 – 2000 18000
7801020 100 2000 13.1 0.26 1335 – 4000 18000
7801025 100 2500 13 0.26 1670 – 5000 18000
7801030 100 3000 12.9 0.26 2000 – 6000 18000
7801042 100 4200 12.7 0.25 2800 – 8400 18000
7801048 100 4800 12.6 0.25 3230 – 9600 18000
7801055 100 5500 12.5 0.25 3670 – 11000 18000
7801062 100 6200 12.3 0.24 4130 – 12400 18000
7801072 100 7200 12 0.24 4800 – 14400 18000
7801088 100 8750 11.5 0.23 5830 – 17500 18000
7801097 100 9700 11.1 0.22 6470 – 18000 18000
7801103 100 10300 10.9 0.21 6870 – 18000 18000
7875070 75 7000 16.7 0.33 4670 – 14000 24000
7875095 75 9500 16 0.32 6330 – 19000 24000
7850010 50 1000 26.4 0.52 670 – 2000 36000
7850038 50 3800 26.2 0.52 2530 – 7600 36000
7850063 50 6300 25.8 0.51 4200 – 12600 36000
7850070 50 7000 25.7 0.51 4670 – 14000 36000
7850083 50 8300 25.5 0.5 5530 – 16600 36000
7850124 50 12400 24.6 0.48 8240 – 24820 36000
7850169 50 16900 23.2 0.46 11270 – 33800 36000
7850200 50 20000 22 0.43 13330 – 36000 36000
7837028 37.5 2800 35.1 0.69 18700 – 5600 48000
7837056 37.5 5600 34.8 0.69 3735 – 11200 48000
7837093 37.5 9300 34.3 0.68 6200 – 18600 48000
7837156 37.5 15600 33 0.65 10400 – 31200 48000
7824116 24 11600 54 1.1 7730 – 23200 75000
7824144 24 14400 53.6 1.1 9600 – 28800 75000
7824173 24 17300 53.1 1.1 11530 – 34600 75000
7824243 24 24300 51.6 1 16200 – 48600 75000
7824285 24 28500 50.5 1 19000 – 57000 75000
7824325 24 32500 49.2 1 21670 – 65000 75000

 

* at the blaze wavelength

** at the wavelength 255 nm

For blaze wavelength 2000 nm and shorter the data measured by multielement detectors with entrance slit 15 microns.

For the wavelength more than 2000 nm the data obtained by calculation with the entrance slit 15 microns.