| Model 2035 Double Monochromator for Additive or Subtractive Mode Operation
Double spectrometers are used for a variety of applications which require extremely low levels of scattered or stray light. The most popular applications include:
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The Model 2035 Double is configured by joining two individual instruments into a double spectrometer with either additive or subtractive dispersion. The double additive monochromators may include mechanical linkage of two sine drives and wavelength control via a single motor (Model 789A-3 high resolution scan drive.) The optimal system tracking is attained by using two 789A-3 scan controls, one for each instrument. This allows optimization in software for best tracking at various wavelengths. The data shown here is collected with mechanically linked systems. System with two scan controls produce even better numbers.
Low Stray Light Stray light is frequently characterized by laser sources and instruments equipped with holographic gratings. This approach yields impressively small numbers and yet, is not very pertinent for many applications. Using a laser source and measuring at 10 bandpasses from a laser line describes Raman or weak luminescence experiments but does not address source and detector characterization applications. The latter frequently employ broadband and/or continuum sources.
| Wavelength | with filter | w/out filter | Percent Stray Light |
| 340 nm | 4*10^-10 | 4.8*10^-5 | 0.0008 |
| 350 nm | 3.8*10^-10 | 2.9*10^-5 | 0.0013 |
| 400 nm | 1.6*10^-9 | 5.2*10^-4 | 0.0003t |
Specifying Stray Light The United Kingdom standards organization, National Physics Laboratory (NPL) defined this procedure for specifying stray light when continuum sources are used. Scattered light is measured at a particular wavelength with and without a particular long pass filter in front of the slit. Depending on wavelength and filter used, the ratio of the background signal - with and without the filter - was between 0.3 - 1.3 X 10-5. Scatter represents less than 0.0015% even with a continuum source entering the instrument. NPL requirements specify better than 0.05%.
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The Model 2035 optical system is optimized for two modes of operation. Instruments may be equipped with spherical optics for optimal spectral resolution. Spherical optics introduce astigmatism to the system that is not desirable in multi-channel fiber or other imaging applications. Configured for imaging the Model 2035 is equipped with an asphere to reduce astigmatism. Learn about the Model 2035 for imaging here.
PDF format Data Sheet for the high throughput Model 2035D (Double) available here
Model 2035 Salient Features
- Exit ports may be equipped with bilaterally adjustable slits, as used in scanning applications, or with adapters for selected CCD or PDA array detectors.
- Holds chosen ruled or holographic gratings.
- Available with a dual (2) grating turret. Single gratings feature kinematic mounts for ease of installation and exchange. Both types of grating holders permit simple and precise positioning. Additional gratings can easily be installed.
- Robust, high accuracy wavelength drive and mechanical wavelength readout insure easy use. The sine drive delivers a linear relationship between motor motion and wavelength of interest.
- The high precision drive may be actuated manually, via stepper motor controller or from the PC.
- Supplied with side and/or front mounted slit assemblies. Side ports are accessed by 90-degree mirror assemblies which are optionally motor driven.
- Imaging optical system easily adapts to commercial PDA and CCD type detectors. The mechanical interface for uncommon detectors will be manufactured to order.
- Precision bilaterally adjustable slit assemblies. Width is variable by micrometer from 10-um to 4-mm. The micrometer is directly readable to 10-um. Slit height is adjusted by occulter from 2-mm to 20-mm. The slits are optionally motor driven.
- The wide range of available accessories allows configuration of optimized systems and facilitates changing experimental needs.
- Heavy duty aluminum construction for high stability with respect to vibration and thermal effects.
- Outperforms and exceeds specifications of comparable monochromators in resolution, dispersion, wavelength accuracy, and wavelength reproducibility.
Most of our instruments are used in research. We try to collect the publications of authors which used our instruments in order to provide ideas of applications to our customers. Bellow are few of them:
- Resonance Raman study of the phonon spectra in superconducting Bi-2212 and Y-123
- Fully reflective deep ultraviolet to near infrared spectrometer and entrance optics for resonance Raman spectroscopy
- Orbital ordering in LaMnO3 investigated by resonance Raman spectroscopy
- Primary realization of a spectral irradiance scale employing monochromator-based cryogenic radiometry between 200 nm and 20 µm
- Picosecond relaxation of Ni-centers in II–VI semiconductors
- Picosecond energy transfer between excitons and defects in II-IV semiconductors