Raman Commander
Work closer to the Raligh scatter with the Raman Commander. Use the f/4.8 aperture to collect more precious photons. The all reflective optical system works fine in the UV. The double subtractive 350-mm focal length pre- monochromator is efficient. There are many available gratings capable of getting you to within 20cm-1. The spectrometer stage can be f/4.7 670-mm when you need the most light or specify f/9.4 1330-mm. The latter provides wonderful symetrical line profiles and resolution of 0.3cm-1.
The Raman Commander is a research tool everyone can use. Reflective optics with optimized coatings provide good efficiency in the ultraviolet (UV.)
Features: The entire optical train uses reflective optics to enable the wide wavelength range without refocusing. The high performance subtractive double pre-monochromator is used for band selection and edge formation. The pre-spectrometer utilizes aberration corrected holographic gratings for best efficiency and imaging. The holographic gratings have high fidelity surfaces further reducing scatter. The slits are continuously adjustable and together with the high precision drive system flexibly tune the image location and optimize rejection.
Specifications
| Focal Length | First stage: 350 mm, Second stage: 350 mm, Third stage: 670 mm (optional 1.33m) |
| Slit Locations | Axial or Lateral. Second entrance direct to Spectrograph stage. Double pre monochromator can also be used as sotand alone double or single. |
| Slits | 0.01 to 4 mm wide; 2 to 20 mm high |
| Slits (Subtractive intermediate) | 0.025 to 10 mm wide; 0.025 to 10 mm high |
| Slits (Spectrograph entrance) | 0.01 to 4 mm wide; 2 to 20 mm high |
| f / No. | f/4.8 (optional 9.4) |
| Dispersion | 0.83nm/mm (optional 0.41nm/mm) with 1800g/mm, Spectrograph stage. |
| Resolution | 1 cm^-1 at 500nm; 4 cm^-1 at 244nm (optional 0.3cm^-1 at 500nm; 1.2cm^-1 at 244nm) |
| Grating Size | (2X) 68*68mm and (1X) 120 x 140mm; select from many gratings including original (master) high fidelity holographic gratings |
| Drive Mechanism | Sine bar |
| Step Size | 0.0002 nm |
| Wavelength Accuracy | +/-0.2-nm (on counter, with 1200 G/mm grating) |
| Wavelength Reproducibility | +/- 0.005 nm (with 1200 G/mm grating) |
| Focal Plane | 50-mm, multiply dispersion by the width of detector for range |
| Wavelength Range | refer to grating of interest for range |
| Grating | Mechanical Range | CCD Coverage** | Resolution*** |
| 300 | 0 to 6000 | 126-nm | 4.8cm-1 |
| 600 | 0 to 3000 | 63-nm | 2.4cm-1 |
| 1200 | 0 to 1500 | 32-nm | 1.2cm-1 |
| 1800 | 0 to 1000 | 21-nm | 0.8cm-1 |
| 2400 | 0 to 750 | 16-nm | 0.7cm-1 |
| 3600 | 0 to 500 | 11-nm | 0.5cm-1 |
| Grating | Mechanical Range | CCD Coverage** | Resolution*** |
| 300 | 0 to 6000 | 66-nm | 1.6cm-1 |
| 600 | 0 to 3000 | 33-nm | 0.8cm-1 |
| 1200 | 0 to 1500 | 16-nm | 0.4cm-1 |
| 1800 | 0 to 1000 | 11-nm | 0.3cm-1 |
| 2400 | 0 to 750 | 8-nm | 0.2cm-1 |
| 3600 | 0 to 500 | 5-nm | 0.16cm-1 |
* To work through a wide range, eg. 185 to 1000-nm efficiently, more than one grating may be required.
**1-nm corresponds to about...
170cm-1 at 240 nm
40cm-1 at 500 nm
15cm-1 at 750 nm
*** Resolution relative to 500-nm, scanned with 10-um wide slit
The Triple Monochromator Spectrometer consists of three separate, fast, high performance monochromators coupled to form a versatile tool for research. The unique properties of this system include aggressive aperture ratio (f/4.8 or better, system wide,) and precise and reproducible wavelength drives. The combination of instruments delivers extremely good solid angle collection from weakly emitting samples, stray light rejection and freedom to tune through a wide spectral range.
Optical Schematic for the Raman Commander
The first two instruments, f/4.8 350mm focal length McPherson Model 2035 monochromators work together as a double monochromator with subtractive-dispersion (DS) filter-stage, useful for Raman or PL applications. The output of the 2035DS instrument forms at the entrance plane to the f/4.7 667mm focal length McPherson Model 207.
The double monochromator, filter stage instrument features a variable-size middle, or intermediate aperture. Used at smaller settings this aperture behaves much like a monochromator slit. With larger openings, the intermediate slit allows the user to set an expanded bandpass for subsequent viewing and analysis. To generalize, small intermediate aperture settings may be most useful in scanning mode applications, large ones with CCD array detection.
The Model 207 monochromator is the main dispersive instrument for the system and is responsible for final image formation and spectral-resolution. It takes the bandpass selected by the intermediate slit of the double-subtractive stage and disperses it across the detector. This instrument is equipped with a CCD detector as well as an auxiliary entrance and exit port, each one equipped with bilaterally adjustable slits. At the exit, the extra slit may be useful for mounting a photomultiplier or other detector for scanning. At the entrance, it is possible to employ other and diverse sources (notch filters for other Raman work, calibration lamps, etc.)