Raman Spectroscopy
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Schematic of a Raman spectrometer. Depending on the model, the Gel Grating P&P Optica system can acquire data using slit length of up to 25mm with spectral resolution reaching below 1cm-1. Excitation wavelengths of 242nm up to 1064nm can be used with the appropriate model. |
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Exceptional SNR Coupled with Very High Throughput |
P&P Optica’s non-scanning Raman, Gel Grating based spectrometers are well suited to provide real-time quantitative analysis of chemical compositions in gas, liquid and solid mixtures. Since Raman spectroscopy measures the vibration frequencies of molecules, it provides information regarding their molecular structure and contains both a unique fingerprint and quantitative information regarding the molecules present in the sample under examination. One of the most significant laser Raman advantages is that it provides excellent differentiation of species compared with techniques of comparable sensitivity such as mass spectrometry and chromatography.
PPO-RAMAN SPECTROMETER
- Combined power of high efficiency transmission technology and the use of large detector array for ultra-high signal-to-noise ratio (SNR)
- Non-scanning system enables low-light, time dependent measurements.
- Modular design for multiple different Raman applications (microscopy, imaging, multichannel Raman)
- Equivalent performance with less expensive cameras
Volume phase holographic transmission grating technology maximizes the number of photons reaching the detector and dramatically reduces “noisy photons” which contribute in masking weak Raman signals. P&P Optica’s proprietary transmission grating fabrication process produces the best transmission gratings in the market today. The following Figure compares PPO’s grating with two leading competitors:
| P&P Optica | Competitor 1 | Competitor 2 |
All results were taken with a 632.8nm He-Ne laser at same laser power and for the Bragg condition.
Scientific cameras are very expensive and essential laboratory equipment. You want to make sure that you take full advantage of your investment’s capabilities. Because of its patented optical design, PPO-Raman spectrometers can effectively illuminate large CCD arrays without optical aberrations which enables binning of the entire array leading to dramatic increases to the SNR. Like the following figure illustrates, such is not the case of current spectrometers:
| Spectral Bandwidth | Dependent on excitation and falling within the 250 nm – 2500 nm spectral region. |
| Excitation Wavelengths | 248 nm, 355 nm, 532 nm, 633 nm, 785 nm, 832 nm, 1064 nm and others |
| Absolute Diffraction Grating Efficiency as Placed in the Spectrometer | Peak: >95%, average: 70-90%; depending on bandwidth and resolution. |
| Stray Light | <1x10-5 or 0.001% |
| SNR Multiplier | Up to 45x increase in SNR1, camera dependent. |
| Dispersion (nm/pixel) | <0.025 |
| Spectral Resolution (nm) | <0.05, wavelength and bandwidth dependent. |
| Camera Options | Standard scientific cameras, including back thinned CCD, front illuminated CCD, low noise CMOS, EMCCD and others. Cameras are selected to provide best price to performance. Maximum usable size: 28 x 14 mm. |
| Slit Length | Variable, matching detector size up to 25 mm. |
| Slit Width | Fixed or variable, selected to optimize resolution versus signal throughput (minimum 5 microns). |
| Optical Inputs | Multimode or single mode fibers in varying configurations such as spot to line, connectorized with FC/APC, SMA or other connectors. Other, non-fiber collection options also available. |
| Shutter | Optional, mechanical, opening/closing the entire input slit linearly. Minimum acquisition time: 10 ms. |
| Dimensions | 10 cm x 11 cm x 28 cm |
| Weight | <3 kg |
1 SNR multiplier is a value calculated by taking the square root of the number of rows on a detector used in binning mode. PPO’s patented optical design allows us to illuminate large CCD or CMOS arrays with no optical abberations. This allows a dramatic increase in the SNR of the Raman signal.
