Co:Spinel (Cobalt-doped magnesium aluminate spinel; Co:MgAl2O4) allows the generation of a short nanosecond pulse with high peak power around the eye-safe wavelength of 1.5um, perfect for telemetry applications. The absorption spectrum of Co2+-doped MgAl2O4 exhibited a broad absorption band in the wavelength range of 1200–1600 nm, which indicated that Co2+ ions substituted for the tetrahedrally coordinated Mg2+ ions in the MgAl2O4 lattice. Passive Q-switching of solid-state lasers with solid-state saturable absorbers is a beautiful Q-switching technique. It allows the development of compact and low-cost laser sources of nano and sub-nanosecond pulses for various applications.
Co:Spinel——saturable absorbers for the passive Q-switching of solid-state lasers operating at an eye-safe wavelength of 1.5 μm
Lasers emitting at 1.5µm are of great interest for several industrial applications. This interest is, first of all, due to the eye safety of 1.5-µm radiation. Other advantages of this wavelength are high transparency in the atmosphere and fused silica waveguides and the availability of sensitive room-temperature light detectors(Ge and InGaAs photodiodes). All this makes 1.5µm lasers very attractive for applications in range-finder, environmental sensing, telecommunications, surgery, etc. Co:Spinel absorption peak is close to 1520nm, primarily used in eye-safe lasers. The absorption cross-section at 1520nm is 3.5×10-19cm2 and at 1331 is 2.8×10-19cm2. It has been reported as a Q-switch crystal for Er,Yb Glass, Nd:GYSGG,Nd:YALO3.
Co:Spinel for 1535nm Laser Passive Q-Switch
Size:10*10*2.046;
T0=95%;
S1: AR@1535±5nm, S2: PR@1535±5nm, R=92%/ R=95%
Co:Spinel crystal case (2)
Size: 4.2*4.2 (+/-0.2) mm;
Thickness: 1.5 (+/- 0.5);
Initial Transmission: 95% (+/-0.5%);
Coating, S1/S2: AR/AR@1540nm
Co:Spinel crystal case (3)
Dimensions, mm: Ø6;
Thickness, mm: 1;
Initial transmission: 90 +/-0.5%;
Surface quality, S-D: 20-10
Co:Spinel crystal case (4)
Size: Φ6×1 mm;
End surfaces configuration: Plano/Plano;
Initial transmission: 90 +/-0.5 %
Co:Spinel crystal case (5)
Size: Φ6×1.145 mm;
2-side polishing
Co:Spinel crystal case (6)
Size: 4.3×4.3×(0.8-1.5) mm
T0=92.5±0.1%@1540 nm
2-side polishing
Co:Spinel crystal case (7)
Size: Ø6×1 mm;
Initial transmission: 90 +/-0.5 %
Radar and Ranging
1535nm laser
Medical Applications
1500nm laser
- Rare excited absorption
- High constant of Q-switch
- High absorption section
- Long excited lifetime
- Evenly distributed cobalt
- Wide absorption band
| Passive shutters for Q-switching continuously diode-pumped Er-glass laser Proceedings of CAOL 2005. Second International Conference on Advanced Optoelectronics and Lasers, 2005 |
| Optical properties of 3d transition-metal-doped MgAl2O4 spinels PHYSICAL REVIEW B 76, 075111 2007 |
| Pressure-induced Co2+ photoluminescence quenching in MgAl2O4 PHYSICAL REVIEW B 86, 125123 (2012) |
| Passive Q-switchlng of 1.34pm neodymium laser using Co:LiGs5O8 and Co:MgAl2O4 Conference Digest. 2000 Conference on Lasers and Electro-Optics Europe (Cat. No.00TH8505) |
| Nd:GYSGG laser at 1331.6 nm passively Q-switched by a Co:MgAl2O4 crystal Optical Materials Volume 69, July 2017, Pages 250-253 |
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| Czochralski growth and characterization of MgAl2O4 single crystals Journal of Crystal Growth Volume 401, 1 September 2014, Pages 844-848 |
| Effect of Co2+ substitution on MgAl2O4 studied by infrared reflectance spectroscopy Optik Volume 147, October 2017, Pages 180-186 |
| Thermal analysis of a diffusion bonded Er3+,Yb3+:glass/Co2+: MgAl2O4 microchip lasers Optical Materials Volume 60, October 2016, Pages 546-551 |
| Comparison of laser generation in thermally bonded and unbonded Er3+,Yb3+:glass/Co2+:MgAl2O4 microchip lasers Optical Materials Volume 46, August 2015, Pages 561-564 |
| Preparation and optical properties of nanoscale MgAl2O4 powders doped with Co2+ ions- Journal of Non-Crystalline Solids Volume 354, Issue 29, 1 July 2008, Pages 3516-3519 |
| Nonlinear absorption properties of Co2+:MgAl2O4 crystal Appl. Phys. B 70, 179–184 (2000) / Digital Object Identifier (DOI) 10.1007/s003409900138 |
| Effect of Co2+ Ions Doping on the Structural and Optical Properties of Magnesium Aluminate Journal of ELECTRONIC MATERIALS, Vol. 46, No. 7, 2017 |
| Optimized diode-pumped passive Q-switched ytterbium–erbium glass laser Appl Phys B (2012) 108:283–288 DOI 10.1007/s00340-012-5036-3 |
| Passive Q-switching at 1.54 μm of an Er–Yb: GdCa4O(BO3)3 laser with a Co2+: MgAl2O4 saturable absorber Appl. Phys. B 81, 49–52 (2005) |
| Spectroscopy, continuous-wave and Q-switched diode-pumped laser operation of Er3+,Yb3+:YVO4 crystal Appl.Phys.B86,275–278(2007) |
| Monolithic thermally bonded Er3+, Yb3+:glass/Co2+:MgAl2O4 microchip lasers Optics Communications Volume 356, 1 December 2015, Pages 166-169 |
| Absorption and photoluminescence characteristics of Co2+:MgAl2O4 nanocrystals embedded in sol–gel derived SiO2-based glass Optical Materials Volume 25, Issue 1, February 2004, Pages 65-69 |
| Passive Q-switching at 1645 nm of Er:YAG Laser with Co:MALO Saturable Absorber IQEC/CLEO Pacific Rim 2011 ● 28 August – 1 September 2011 ● Sydney, Australia |
| Optimizationof passively Q-switched Er:Yb:Cr:phosphateglass laser: theoretical analysis and experimental results Appl.Phys.B86,293–301(2007) |
| Pulse energy optimizationof passively Q-switched flash-lamp pumped Er:glass laser Appl.Phys.B75,35–39(2002) |
Methods and Processes of Co doped Spinel Crystal Growth – 2020/10/20 – CRYLINK
Parameter
| Property | Value |
| Chemical formula | Co2+:MgAl2O4 |
| Crystal structure | Cubic |
| Lattice parameters | 8.07Å |
| Density | 3.62 g/cm3 |
| Melting Point | 2105°C |
| Refractive Index | n=1.6948 @1.54 μm |
| Thermal Conductivity/(W·cm-1·K-1@25°C) | 0.033W |
| Thermal Expansion /（10-6 /°C@25°C ） | 1.046 |
| Specific Heat/ (J·g-1·K-1) | 5.9 |
| Hardness (Mohs) | 8.2 |
| Extinction Ratio | 25dB |
| Orientation | [100] or [111] < ±0.5° |
| Optical density | 0.1-0.9 |
| Damage Threshold | >500 MW/cm2 |
| Doping concentration of Co2+ | 0.01-0.3 atm% |
| Property | Value |
| Concentrations | (0.05~0.35) wt% |
| Absorption coefficient | 0 ～ 7 cm-1 |
| Ground-state absorption cross-section GSA(E-19 cm2) | 2.8（±0.4）@1340nm |
| Excited state absorption cross-section ESA(E-20 cm2) | 2.0（±0.6）@1340nm |
| Ground-state absorption cross-section GSA(E-20 cm2) | 3.5（±0.4）@1540nm |
| Excited state absorption cross-section ESA(E-20 cm2) | 1.0（±0.6）@1540nm |
| Working wavelength | 1200 – 1600 nm |
| End Configuration | Flat/Flat |
| Figure of Merit(FOM) | 100~300 |
| Coatings | AR/AR@1540，R<0.2%; AR/AR@1340，R<0.2% |
