Study On Mid-Infrared Luminescence Properties Of Rare Earth Ion Doped Fluorine-Indium Based Glass Fiber

Fiber lasers have remarkable superiority over other kinds of lasers in terms of volume bulk and laser beam quality.Long-wavelength,high-power mid-infrared lasers cannot be developed using conventional quartz optical fibers because of their high phonon energy(?1100 cm^-1)and high transmission loss in the mid-infrared band.Therefore,long wavelength,high-output mid-IR lasers cannot be developed using conventional quartz fiber.Laser systems with wavelengths ranging from 2 to 5?m have very important applications in science and industry.This spectral range is characterized by strong absorption lines for molecules such as water elements,carbon nitrous oxide,formaldehyde,CH₄ and glucose(C₆H₁₂O₆),and hydroxyl groups,which are used in a range of fields from fundamental research to experimental processing.The current research on mid-infrared laser based on Tm³⁺,Ho³⁺,Er³⁺doping is mainly limited to ZBLAN fiber,but the easy deliquescence and low political and mechanical properties of ZBLAN matrix material restrict its development in long wavelength and high power.In this paper,We use indium fluoride-based glass fiber as the matrix material to explore the fluorescence properties of Tm³⁺at 1480 nm,1820 nm,and 2320nm,and analyze the possibility of its realization in Chinese and foreign lasers.(1)In this experiment,the Tm³⁺-doped indium fluoride-based glass was prepared by the traditional melting method,and the related properties were measured and calculated in detail.The phonon energy is 510 cm^-1,the core(IZGP)and the small cladding(IZGN)both have similar transition temperatures and larger?T values,indicating that both the core and the cladding have good glass-forming and anti-deposition properties.Crystal performance is conducive to the drawing of optical fiber.The numerical aperture NA(2.3?m)is 0.36,and a larger numerical aperture is conducive to the transmission of laser light in the optical fiber.Compared with Tm³⁺in ZBLAN glass,Tm³⁺has a higher maximum emission cross section at 2320 nm.The largest emission cross section of Tm³⁺in indium fluoride based glass is 3.67×10^-21 cm².Based on the characterization of glass materials,it can be seen that indium fluoride-based glass has excellent thermal and optical properties.(2)After exploring the excellent properties of indium fluoride-based glass,a glass fiber with a doping concentration of 0.7 mol%Tm³⁺was drawn,and its fluorescence properties at various wavelengths were explored.The Tm³⁺-doped indium fluoride based glass fiber produced a bright blue upswitching phenomenon under the excitation of a pumplight source at 1120 nm,and a 1680 nm luminescence spectrum not observed in glass was observed.Under the excitation of different pump powers,the luminescence spectra of each wavelength did not appear absorption saturation.The stronger luminescence spectra indicate that increasing the pump power is expected to achieve?2.3?m laser output.(3)Based on the above phenomenon,the method of Tm³⁺/Ho³⁺co-doping was explored,aiming to increase the?2.3?m luminescence intensity of Tm³⁺ion-doped indium fluoride-based glass by changing the concentration of sensitizing ions.The experimental results prove that the luminescence intensity of Tm³⁺ions in the 1480 nm band is enhanced by co-doping.This research provides a new research direction for the expansion of S-band(1460-1530 nm)optical amplification technology in the communication field.The energy transfer effect enhances the?2?m fluorescence intensity generated by the Ho³⁺:⁵I₇?⁵I₈ radiation transition,which provides a basis for the?2?m laser research.Tm³⁺:³H₄?³H₅ radiation transition produced?2.3?m fluorescence intensity weakened,mainly because the introduction of sensitizer ions caused the?2.3?m fluorescence upper and lower energy level inversion particles decreased.