Tm:YLF
Tm:YLF is the important middle infrared laser crystal. Because Tm:YLF is negative uniaxial crystal, whose thermal refractive index coefficient is negative, some thermal distortion may be counteracted and high-quality light can be output. Conveniently pumped at 792nm, 1.9μm linearly polarized beam is output in a axis, and non-linearly polarized beam is output in c axis. The YLF crystals has low non-linear refraction index value and thermo optical constants, which makes theses crystals applicable in research, development, education, production, photonics, optic, laser technology and telecommunications.
Tm3+:YLF lasers are ideal to be used as pump source for Ho3+:YAG lasers.
Yttrium lithium fluoride (YLF) is a particularly attractive choice as the host medium for thulium, when it is used as pump source for a 2.1 μm Ho:YAG laser. This is due to the good overlap of the emission peaks with the absorption spectrum of Ho:YAG. YLF is a naturally birefringent material, capable of producing linearly polarized output with virtually no depolarization loss.
Parameter
| Concentration Tolerance (atm%) | 2-4 at.% |
| Lattice Constants | 4~5 |
| Orientation | a-cut, other orientations also available |
| Parallelism | <10” |
| Perpendicularity | <5” |
| Surface Quality | 10-5 scratch & dig |
| Wavefront Distortion | λ/8 @ 633nm |
| Surface Flatness | λ/10 @ 633nm |
| Clear Aperture | 95% |
| Length Tolerance | ±0.1 mm |
| Face Dimensions Tolerance | +0/-0,1 mm |
| Protective Chamfers | <0,1 mm at 45˚ |
| Damage Threshold | over 15J/cm2 TEM00, 10ns, 10Hz |
| Crystal Structure | Tetragonal |
| Lattice Constants | a=5.16Å; c=10.85Å |
| Density | 3.99 g/cm³ |
| Melting Point | 819℃ |
| Thermal Conductivity | 6 Wm-1K-1 |
| Thermal Optical Coefficient(dn/dT) | π = 4.3 x 10-6 x °K-1; σ = 2.0 x 10-6 x °K-1 |
| Thermal Expansion /（10-6·K-1@25°C ） | 10.1×10-6 (//c) K-1, 14.3×10-6((//a) K-1 |
| Hardness (Mohs) | 5 |
| Shear Modulus /Gpa | 85 |
| Specific Heat | 0.79 J/gK |
| Poisson Ratio | 0.3 |
| Laser Transition | 3F4→3H6 |
| Laser Wavelength | π:1880 nm; σ:1908 nm |
| Absorption Cross-section at Peak | 0.55×10-20 cm2 |
| Absorption Bandwidth at Peak Wavelength | 16 nm |
| Absorption Peak Wavelength | 792 nm |
| Lifetime of 3F4 Thulium Energy Level | 16 ms |
| Quantum Efficiency | 2 |
| Non-linear Index n2 | 0.6 x 10-13 |
| Optical Quality | < 0.3 x 10-5 |
| Refractive Index @1064 nm | no=1.448, ne=1.470 |
| Laser Induced Damage Threshold | >10 J/cm2@1900 nm, 10 ns |
| Coatings | R<0,5% @792 nm + R<0,15% @1800-1960 nm on both sides; custom coatings also available |
Feature
- Linearly polarized output beam
- Little heat effect while laser
- Effective cross relaxing of Tm ions
- Relatively high efficiency with LD pumping
- Low nonlinear refractive index
- Low thermo-optical constant
- Low polarization loss
- Long upper energy level fluorescence lifetime
- Small up-conversion effect
- No absorption loss of sensitized ions
Application
- Medical diagnosis and treatment
- Laser radar
- Laser ranging
- Electro-optical countermeasure
- Laser remote sensing
- Laser imaging
- Optical signal processing
- Material processing
- Pump source for Ho3+:YAG lasers
Literature
| [1] Jing, Wu, Lin, et al. Tunable single-longitudinal-mode operation of a sandwich-type YAG/Ho:YAG/YAG ceramic laser[J]. Infrared Physics & Technology, 2016. |
| [2] Cao L , Tang W , Zhao S , et al. 2 μm Passively Q-switched all-solid-state laser based on WSe2 saturable absorber[J]. Optics & Laser Technology, 2019, 113:72-76. |
| [3] Fan Z , Wen Y , Shi X , et al. LD double-end pumped dual-rod acousto-optic Q-switched Tm:LuAG laser[J]. Infrared Physics & Technology, 2019, 102:103022. |
| [4] Guo L , Zhao S , Li T , et al. In-band pumped, high-efficiency LGS electro-optically Q-switched 2118 nm Ho:YAP laser with low driving voltage[J]. Optics & Laser Technology, 2020, 126. |
| [5] Wen Y , Li T Y , He Q F , et al. Laser-diode dual-end-pumped electro-optic Q-switched slab Tm:YAP laser[J]. Infrared Physics & Technology, 2020, 105(1):103215. |
| [6] Schellhorn M , Eichhorn M , Kieleck C , et al. High repetition rate mid-infrared laser source[J]. Comptes Rendus Physique, 2007, 8(10):1151-1161. |
| [7] Ding Y , Han L , Yao B Q , et al. High power Tm:YLF bulk laser wavelength-stabilized by two F-P etalons[J]. Optik – International Journal for Light and Electron Optics, 2015, 126(9-10):990-992. |
| [8] W.X. Zhang and J. Zhou and W.B. Liu and J. Li and L. Wang and B.X. Jiang and Y.B. Pan and X.J. Cheng and J.Q. Xu. Fabrication, properties and laser performance of Ho:YAG transparent ceramic[J]. Journal of Alloys and Compounds, 2010. |
| [9] Lia L , Yanga X , Zhoua L , et al. High beam quality passively Q-switched operation of a slab Tm:YLF laser with a MoS2 saturable absorber mirror[J]. Optics & Laser Technology, 2019, 112:39-42. |
| [10] Y, Ding, D . X , et al. High power Tm:YLF laser operating at 1.94 μm[J]. Optik International Journal for Light & Electron Optics, 2015. |
| [11] Yang X T , Mu Y L , Zhao N B . Ho:SSO solid-state saturable-absorber Q switch for pulsed Ho:YAG laser resonantly pumped by a Tm:YLF laser[J]. Optics & Laser Technology, 2018, 107:398-401. |
| [12] Zhang B , Li L , He C , et al. Compact self-Q-switched Tm:YLF laser at 1.91 μm[J]. Optics & Laser Technology, 2018, 100. |
| [13] Yuan J , Chen Y , Duan X , et al. CdSe optical parametric oscillator operating at 12.07m with 170mW output[J]. Optics & Laser Technology, 2017, 92:1-4. |
| [14] Dai Y , Li Y , Zou X , et al. Compact passively Q-switched Tm:YLF laser with a polycrystalline Cr:ZnS saturable absorber[J]. Optics & Laser Technology, 2014, 57:202-205. |
| [15] Zhang X , Chu H , Li Y , et al. Diameter-selected single-walled carbon nanotubes for the passive Q-switching operation at 2 μm[J]. Optical Materials, 2020, 100(Feb.):109627.1-109627.4. |
| [16] Zhang Y , Cai Y , Xu B , et al. Extending the wavelength tunability from 2.01 to 2.1 μm and simultaneous dual-wavelength operation at 2.05 and 2.3 μm in diode-pumped Tm:YLF lasers[J]. Journal of Luminescence, 2019, 218. |
| [17] Duan X M , Ding Y , Dai T Y , et al. A linewidth-narrowed Tm:YLF laser using by two etalons[J]. Optik – International Journal for Light and Electron Optics, 2015, 126(19):2108-2109. |
| [18] Pan H , Huang W , Chu H , et al. Bismuthene quantum dots based optical modulator for MIR lasers at 2 μm[J]. Optical Materials, 2020, 102. |
| [19] Cui Z , Yao B Q , Duan X M , et al. A graphene saturable absorber for a Tm:YLF pumped passively Q-switched Ho:LuAG laser[J]. Optik – International Journal for Light and Electron Optics, 2016, 127(5):3082-3085. |
| [20] Wang R , Li Y , Zhang L , et al. Passively Q-switched mode-locked Nd:GdTaO4 laser by rhenium diselenide saturable absorber operated at 1066 nm[J]. Infrared Physics & Technology, 2020, 108:103378. |
| [21] Zhang X , Ni K , Huang J , et al. Resonantly pumped mid-infrared Ho:YAG/BaWO4 intracavity Raman laser at 2640 nm[J]. Optics & Laser Technology, 2020, 121:105813. |
| [22] Wang, Shiqiang, Huang,等. Rhenium diselenide as the broadband saturable absorber for the nanosecond passively Q-switched thulium solid-state lasers. |
| [23] Zhang W , Bai H L , Guo L P , et al. Self-Q-switched operation in Tm:YAG crystal and passively Q-switched operation using GaSe saturable absorber[J]. Infrared Physics & Technology, 2020, 105:103208. |
| [24] Razumova I , Tkachuk A , Nikitichev A , et al. Spectral-luminescent properties of Tm:YLF crystal[J]. JOURNAL OF ALLOYS AND COMPOUNDS, 1995, 225(1-2):129-132. |
| [25] Yuan J H , Yao B Q , Duan X M , et al. Resonantly pumped high power acousto-optical Q-switched Ho:YAG ceramic laser[J]. Optik – International Journal for Light and Electron Optics, 2016, 127(4):1595-1598. |
| [26] Low-Cost Multi-Mode Diode Pumped Tm:YLF Laser: Multi-Color & Q-Switching Operations[J]. Optics Communications, 2019, 451:55-61. |
| [27] Yue, Chen, Xin-Yu, et al. A compact high efficient Tm:YLF laser dual-end-pumped by an equidirectional-polarizing fiber coupled laser diode at room temperature[J]. Optik: Zeitschrift fur Licht- und Elektronenoptik: = Journal for Light-and Electronoptic, 2018, 158:1553-1557. |
| [28] Yokozawa T , Izawa J , Hara H . Mode control of a Tm:YLF microchip laser by a multiple resonator[J]. Optics Communications, 1998, 145( 1–6):98-100. |
| [29] Duan X M , Shen Y J , Yao B Q , et al. A 106W Q-switched Ho:YAG laser with single crystal[J]. Optik – International Journal for Light and Electron Optics, 2018, 169:224-227. |
| [30] Hu H , Huang H , Huang J , et al. Tm:YVO4 laser intra-cavity pumped 2.1μm Ho laser – ScienceDirect[J]. Optics Communications, 472. |
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