Gemological studies with the Renishaw Raman microscope

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emission
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emission
?excitation
?excit.-?vib.
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High spatial resolution ??????(????,????????

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Non-destructive analysis ????
Almost no sample preparation ????????
Very small amount of sample???????
Characteristic vibrational spectrum ??????
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Information obtained from Raman spectroscopy
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• ????????????1010-1014,??????????
• ?????????,??????????,???????(?????????????
  ),???????????

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Renishaw????????
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• ?? 1. ????
• ??????????????
• ????????(??1440 cm-1)?????101,???????????20mW,?
  ?514.5nm,????50??,????60?,????5?,binning?1?2,???18
  00???????? X50?????

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?Renishaw inVia????????????????????????
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?? 2. ????????? ????????????????
- ?????????????
- ??????????????, ????????????????
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• ??? 0.2 µm,???????????????10?
• ?? 0.1 µm (x- and y-axes)1 µm (z-axis)

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grating and wavelength dependent
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14220 cm-1 14430 cm-1 14885 cm-1 14971 cm-1
D Frequency cm-1
This error plot show that during normal working
day all the errors track and the typical errors
are less than 0.05 cm-1
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• ??30?????????????????????
• ??2???????????????????????
• ??????????????(????????????) ???????0.06 cm-1

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Frequency shift due to stress
tensile
compressive
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?????????
???????
???? ????
µm
Intensity / counts
1 s exposure per spectrum (51x512601 spectra)
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??????????

• ?? 3. ??????????(SynchroScan)
• (Patent No. EP0638788, US5,689,333)
• ?????????????????(???????),??????,???????????,????
  ???,???????????????

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• ??????(SynchroScan)
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• CCD?????????????
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• ?????????(9000cm-1??)
• ????CCD?????,????
• ????????,??????
• ?????????????????(??)??????????

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• Renishaw????????????????????????????????????,??
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??Leica???

• ?? 4 ??Leica???
• ???????????
• ??Leica ??,???????????????? a.
  ???,???,??????????? ??????????,???????b.
  ??????????,??????????????????
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  ?,??????
• ????Leica??,?????

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• ?? 5. ?????????????
• ?????????????????,??????,??????????,??????????????
  ??

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?????????????

• ????
• Non-confocal
• Confocal

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?????????????
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OLD
NEW
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??????????????
?????????????

• Sample
• 2 µm thick polyethylene (PE) film
• Thick polypropylene(PP) substrate
• Laser
• 633 nm HeNe
• Spectrometer settings
• Slit width 10 µm

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?????????????

• Conditions
• x50 objective
• focus down through sample from PE to PP
• Results
• weak PP features seen on PE spectrum
• strength increases until only PP seen

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???? - ??????????
?????????????
N2
quartz
H2O
CO2
CH4
Liquid and gas inclusions in quartz
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4
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• ????????????
• ????????,??????
• ???????
• ???????
• ???????????2? ?

????? Using these slits instead of
pinholes makes it easier to make the optical
alignments needed for confocal Raman
measurements. (K.Ajito K. Torimitsu, NTT
Japan Trends in Analytical Chemistry, 20, 2001)
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Sample - SiO2 pattern on Si substrate
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Sample - SiO2 pattern on Si substrate
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Scan over a sharp edge, intensity variation shows
lateral resolution
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?????? ??????????????
?????????????

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Raman microscopy Confocal basics
Lateral spatial resolution
The system laser focus beam waist (dl) is
determined by 1) Excitation wavelength l 2)
Microscope objective focal length f 3)
Effective laser beam diameter at the the
objective backaperture Dl
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???????????????
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?? 6. 1. 16?????????
(??100?5x10-8) 2.
?????????,???????????????(1-250??),?
?????????????????? ?????????????????,????????,
???????????,???????,?????,????????,????????????
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• ?? 7. ??????
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CCD???????
?????????????

• ?? 8. ??????????CCD????
• ???Renishaw??????????
• ??????????????,??????????????????

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CCD???????

• Renishaw inVia
  Series
  Typical Competitor
• ?? EEV 576x398
  EEV
  1024x256
• ???? 12.7mm
  25.6mm
• ?????,CCD????,?????????,??????????????

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???/??????
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• ?Renishaw????,?????????????????????,????????,?????
  ???

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Sample/Application determines required system
resolution
???/??????
Single static scan with 600 l/mm, 10 stitched
static scans with 2400 l/mm
??????? ???????
??? 7 cm-1 (??600 l/mm)
10 ?
??? 1 cm-1 (??2400 l/mm)
60?
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• ?? 10. ???????
• ??????(????,??,????)??
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????? Raman/SEM

• ?SEM???????????????????
• SEM??????
• ????-??-???????????
• ??????
• ?????????????
• ??????

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Sample application - materials science
????? Raman/SEM

• ????
• Diamond - top spectrum
• Silicon carbide - lower spectrum

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????? Raman/AFM/NSOMSEM

• Benefits
• Enhanced spatial resolution (NSOM)
• Enhanced sample imaging (AFM), same area analysis
• Combined software for AFM/Raman image acquisition
  and overlay.

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????? Raman/AFM/NSOM

• Nanonics NSOM/AFM 100
• Renishaw Microscope
• Custom software linking Nanonics and Renishaw
  packaged (Cavendish Instruments Ltd).

University of Sheffield, Dept Chemistry
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????? Raman/AFM/NSOM

• Stress and phases

14 mm
University of Sheffield, Dept Chemistry
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??????? Raman /FTIR

• Raman/FTIR
• ??????
• ???????????(??????)
• ?FT-IR??????????.