Femtosecond Laser Mavericks is based on Chromium-activated Forsterite Single Crystals
Chromium-Doped Forsterite Crystal (Cr:Mg2SiO4) - PX
Chromium-activated Forsterite
Single Crystals, Mg2SiO4:Cr4+,
are excellent
tunable laser crystals for both pulsed and CW lasers.
|
Crystal structure |
Rhombic |
|
Lattice parameter |
a=4.77Å, b=10.28Å, c=6.00Å |
|
Refraction indices |
nz=1.670, ny=1.651, nx=1.635 |
|
Density |
3.217 g/cm3 |
|
Hardness |
7 mohs |
|
Axial Characteristic |
Biaxial |
|
Melting point |
1895°C |
|
Crystal Size (boule) |
Diameter 30 x 140 mm |
|
Damage threshold |
200 MW/cm2 |
|
Saturation energy density |
2J/cm2 |
|
Absorption cross section |
1.88 x 1018 cm2 |
|
Thermal expansion coefficient |
9.5 x 10-6 |
|
Thermal conductivity |
0.08 (300 W/cm°K) |
|
Relaxation time of terminal lasing level |
<10ps |
|
Stimulated emission cross section |
1.44 x 10-19/cm2 |
|
Spontaneous fluorescence |
2.7 x 10-6s |
|
Loss coefficient on wavelength 1230nm |
0.005 - 0.03 / cm |
|
Absorption coefficient on wavelength 1064nm |
0.7 - 2.5 / cm |
|
Fluorescence band |
680 - 1400 nm |
|
Tuning range |
1130 - 1348 nm |
|
Lasing wavelength (centre) |
1235nm (pulsed) |
|
|
1244nm (CW) |
|
Room-temperature fluorescence lifetime |
Appr. 2.7 x 10-8s |
|
Gain cross section |
Appr. 1.45 x 10-19 cm2 |
|
Dopant concentration range |
0.05-0.6% |
|
End face flatness |
l/10 wave across 80% of aperture |
|
Surface roughness |
l/10 |
|
Perpendicularity |
within 5 arc minutes |
|
Parallelism |
30 arc seconds or less |
|
Scratch-dig |
10-10 |
Cr:Forsterite crystal is a new tunable laser material that fills the spectral vacancy in the near-IR region. The tuning range covers the important spectral range from 1167 nm to 1345 nm, which provides a minimal dispersion in optical fibers. The Cr:Forsterite laser eventually explores its niche applications for semiconductor characterization, eye-safe ranging, medical , industrial and scientific research. Both pulsed and continuous-wave (CW) laser operation have been obtained when pumped with 532, 578, 629 and 1064 nm.
Physical, Thermal and Optical Properties - CX
| Chemical Formula | Cr:Mg2SiO4 |
| Concentration | ~3 - 6 x1018 cm-3 |
| Melting Point | 1890 ºC |
| Density | 3.22 g/cm3 |
| Mohs Hardness | 7 |
| Thermal Expansion Coefficient | 9.5x10-6 |
| Thermal Conductivity | 8 W /m /K (300 K) |
| Stimulated Emission Cross Section | 1.44x10-19 cm-2 |
| Relaxation Time of Terminal Lasing Level | <10 ps |
| Radiative Lifetime | 25 ms |
| Spontaneous Fluorescence | 2.7 ms |
| Loss Coefficient | 0.02 cm-1 |
| Refractive Index | 1.635 |
Spectroscopic and Laser Properties
| Major Pumping Bands | 850-1200, 600-850, 350-550 nm |
| Fluorescence Band | 680-1400 nm |
| Room-temperature Fluorescence Lifetime | ~ 3 ms |
| Lasing Wavelength (center) | 1235nm (pulsed), 1244 nm (CW) |
| Spectral Bandwidth | 30 nm (pulsed), 12 nm (CW) |
| Typical Slope Efficiency | 23% (pulsed), 38% (CW) |
| Tuning range | 1167 - 1345 nm |
| Gain Cross Section | ~1.45x10-19 cm2 |