Fluorescence and birefringence |
|
FLUORESCENCE |
|
Almax easyLab can select its diamonds for low fluorescence. Standard measurements include laser excitation at 532 nm and covers fluorescence background in the range of 542 to 608 nm (Raman shifts between 1000 and 3000 cm-1). Measurements for different wavelength ranges can be made available on request. In special cases customers can select their own diamonds for low fluorescence using their own measurement set-up. Almax easyLab classifies its diamonds with respect to fluorescence according to the following criteria:
|
|
1. UV low fluorescence
|
Just checked by a UV lamp. |

|
|
2. Raman low fluorescence
|
The intensity of the two-phonon Raman transition at 2664 cm-1 is at least 1.25 times the intensity of the background fluorescence of diamond. |

|
|
3. Raman ultra low fluorescence
|
The intensity of the two-phonon Raman transition at 2664 cm-1 is at least 2 times the intensity of the background fluorescence of diamond. |

|
|
BIREFRINGENCE |
|
All diamonds to be used for anvil manufacture are examined under a polarising microscope for birefringence. Diamonds with significant birefringence discontinuity, typical of inclusions, etc. are rejected. In addition diamonds can be selected for ultralow birefringence. Total birefringence is measured using crossed polarisers, a waveplate and matched to specifications. Normally: |
1. Low birefringence <0.0001 |
2. Ultra low birefringence <0.00005 |
|
|
Culet size and modification |
Choose culet size as a function of: |
maximum pressure |
culet size |
< 5 GPa |
> 1.00 mm |
5 – 100 GPa |
1.00 mm – 0.20 mm |
> 100 GPa |
<0.20 mm, bevels up to 0.30 mm at 8° |
Note: Typical sample space is given by the gasket thickness (typically 0.10 mm or less) and the central hole diameter (typically 30-50% culet size). |
|
 |
|
Note: single and double bevels are recommended for very high pressure and electrical measurements. |
Note: single bevels around the culet ease the cleaning of the culet and reduce the risk of damage during alignment. |
|
|
|
Examples of typical requests for quote: |
Diamond anvil, type Ia, Standard design, 16-sided, 3.75 mm, culet of 0.10 mm, bevels up to 0.30 at 8°, (100)-oriented, Raman low fluorescence, low birefringence: |
Article nr.: P01008 |
Quantity: 6 anvils. |
Diamond anvil, type Ia, Standard design, 16-sided, 3.25 mm, culet of 0.30 mm, (100)-oriented: |
Article nr.: P01006 |
Quantity: 4 anvils. |
|