(1) What is an Er, Yb: phosphate glass?
The glass doped with Er and ytterbium ions is Er: glass; Glasses doped with erbium, ytterbium, as well as chromium ions are likewise erbium glasses; the double adhered crystal of erbium glass and white glass is also erbium glass. The glass substratum in question is not common glass but phosphate glass. This paper mainly presents Er, Yb doped glass.
Er3+, Yb3+ co-doped phosphate glass (Er, Yb: phosphate glass) is a prominent as well as a normally used active tool for lasers creating in the “eye-safe” scary series of 1,5-1,6 µm.
(2) What is phosphate glass?
Phosphate glass is a glass material that mainly includes phosphorus pentoxide (P2O5) as well as normally also consists of various other chemical elements. It can be utilized as a laser gain medium wholesale as well as fiber. Its primary benefit is its high compatibility with rare-earth ions (see rare-earth-doped gain media), such as Erbium (Er3+), ytterbium (Yb3+), as well as neodymium (Nd3+) ions.
To put it simply, the phosphate glass types can be doped with a high focus of laser-active uncommon earth ions without causing unfavorable effects such as clustering, which will generate a quenching effect and also impact the performance of the laser. The doping concentration in phosphate erbium-doped fiber is much more than that in quartz fiber, and it can enhance by a number of portion factors. The high doping focus of phosphate makes it possible for brief fiber lasers and amplifiers, which are not the only advantages of the glass but also consist of:
The brief fiber laser resonator can get a huge totally free spectrum range, making it simpler to achieve single-frequency operation.
Distributed responses lasers are short, whereas highly doped phosphate fibers enable a lot more efficient pump absorption.
Ultrashort pulsed fiber lasers are much less at risk of nonlinear impacts if they utilize much shorter fibers.
(3) What’s the mechanism of Er: glass?
Phosphate glass incorporates a long lifetime. (~ 8 ms) of 4I13/2 Er3+ top laser degree with a reduced (2-3 ms) lifetime of 4I11/2 Er3+ level that continues to remain in resonance with Yb3+ 2F5/2 terminated upstate. Quick non-radiative multi-phonon entertainment from 4I11/2 to 4I13/2 level considerably reduces the back-energy transfer as well as up-conversion losses. Because of the communication between Yb3+ and also Er3+ ions, delighted at the 2F5/2 together with the 4I11/2 levels, respectively.
Basically constantly, erbium-ytterbium-doped phosphate glass is pumped with wavelengths around the 975-nm absorption height of Yb3+ ions. That results in the excitation of the ytterbium ions. Afterward, Yb ions may transfer the excitation power to bordering erbium ions. After a reliable power transfer, one first has an Er3+ ion in the 4I11/2 state (even more particularly, a Stark level manifold), which has similar excitation power as the Yb3+ ions. From that state, the ions normally undergo a fast non-radiative change to the state 4I13/2, consistently used as the top laser level. Such non-radiative changes take place based upon multi-phonon discharge, offering that the phonon power of the item is high and also ample (which holds for silica fibers, for example).
(4) Application of Er, Yb: glass in Er: glass laser
Er, glass is likewise an exceptional product for upconversion luminescence. Laser obtained the environmentally friendly as well as red laser from erbium-doped glass fiber, and also people likewise observed violet upconversion light. The upconversion luminescence of Er: phosphate glass delighted by Nd: YAG was discovered. The upconversion laser will absolutely be truly functional in lots of applications.
Er, glass is a pure three-level laser tool. Due to this, it requires pumping mostly all the energized glass components. The non-pumped locations give laser light absorption losses. When it comes to the traditional post plan, the non-pumped pole needs to be as brief as viable.
The optical excitation of the Yb, Er glasses (especially chromium-free ones) happens mainly by making use of Yb ions. The only Yb absorption band lies in the near-infrared spooky range (900– 1000 nm). Water discontinuation in this spectral variety is 1 cm-1. Therefore, Er glass can substantially decrease the water-cooled laser performance. As a result of pump light absorption in the water layer bordering the flashlamp and also the laser rod.
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