Ultra High Sensitivity Raman Spectrometer-Even sensitive enough for complex gas Monitoring
Raman Spectroscopy has been widely used in analyze solid and liquid phase sample, but not so much in gas phase sample . Main problem is, normally, the gas phase molecular under the laser illumination is too much less than the same laser illuminate the liquid or solid phase sample. So that, in generally, the Raman signal scattered from the gas phase sample will be too weak to be detected.
There are many instruments can analyze or monitor the gas . for example
1)Absorption spectroscopy related instrument , Normally choose individual LD or LED whichwavelength fix to or tuning to the individual target gas absorption band ,analyze the absorption ratio which is function to the individual gas concentration . This method is cost effective for individual target gas monitoring, could be very high sensitive and accurate based on narrow line laser and Multi-pass optical layout . Not so good for complex gas.
2)Gas Chromatography, high accuracy and sensitivity for complex gas , but it is not good for in situmonitoring because of its time consumption and the consumptive material made it is not so cost effective
3)FT-IR spectroscopy , good for analyze complex gas and less time consumption, nearly noconsumable material need. But the water vapor which often contained in real world gas complex will induce unacceptable noise floor.
Raman Spectroscope is not sensitive to the water vapor, no consumable material need. But because of the low signal level on the gas phase sample , limited the Raman spectroscopy in complex gas analyze and monitoring.
Under the help of Zolix Omni-iSpecT transmission grating imaging spectrometer, an Ultra High Sensitivity Raman Spectrometer can be made, and analyze complex gases in ppm level within a second. It made Raman spectroscopy suitable for gas phase sample analyze and in situ monitoring.
Fig.01 Omni-iSpecT high throughput spectrometer
System Structure
Fig.02 Complex gas analyze and monitor
Sample Test
Limit of detection( LOD unit:ppm)
Fig.03 The ppm level detection limit for complex gas analyze
Fig.04 Raman spectrum of mixed gases with 60s exposure time
Fig.05 Raman spectrum of air with 60s exposure time
The Ultra High Sensitivity come from:
1. The large imagine lens sets inside Omni-iSpecT has very low F#/2.3, made it super high light
throughput.
2. The Volume Phase holographic transmission grating much higher and much smoother efficiency
curve than standard grating.
Fig.06 Diffraction efficiency @532 grating Fig.07 Diffraction efficiency @785 grating
3. High QE cooled CCD( LDC-DD) camera which QE up to 95% and ultra low noise.
Expansion Application:
Omni-iSpecT not only good for complex gas Raman analyze, may also help you improve the
sensitivity of the applications such as：
-Plasma monitoring
- In vivo and in vitro diagnosis
-other low signal level spectrum detection
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