1) What is an “Er,Yb:phosphate glass”?
The glass doped with Er as well as ytterbium ions is Er glass; the glass doped with erbium, ytterbium, and chromium ions is likewise erbium glass; the double-adhesive crystal of erbium glass as well as white glass is additionally erbium glass. This paper generally presents Er,Yb-doped glass. The glass substrate concerned is not typical glass, however; it is phosphate glass.
Er3+ and Yb3+ co-doped phosphate glass (Er,Yb:phosphate glass) is a well-known and widely used energetic material for lasers producing in the “eye-safe” range of 1,5-1,6 um.
2) What is phosphate glass?
Phosphate glass is a type of glass that typically contains phosphorus pentoxide (P2O5) as well as other chemical elements. It can be utilized as a laser gain tool for both wholesale and fiber. Its primary advantage is its high compatibility with rare-earth ions (see rare-earth-doped gain media), such as erbium (Er3+), ytterbium (Yb3+), and neodymium (Nd3+) ions.
Simply put, the phosphate glass species can be doped with a high focus of laser-active unusual planet ions without triggering adverse impacts such as clustering, which will create a quenching effect and impact the performance of the laser.
Phosphate-erbium-doped fiber has a much higher doping concentration than quartz fiber, and it can also be increased by several percentage factors. The high doping concentration of phosphate makes it possible for brief fiber lasers and amplifiers, which are not the only advantages of the glass yet likewise consist of:
- The short fiber laser resonator can get a large cost-free spectrum variety, making it easier to attain single-frequency operation.
- Dispersed feedback lasers are brief, whereas extremely doped phosphate fibers permit extra effective pump absorption.
- Ultrashort pulsed fiber lasers are much less susceptible to nonlinear effects if they make use of much shorter fibers.
3) What’s the device of erbium glass?
Phosphate glass combines a long lifetime (8 ms) of 4I13/2 Er3+ leading laser level with a short lifetime (2-3 ms) of 4I11/2 Er3+ degree that remains in resonance with Yb3+ 2F5/2 terminated up state. Quick non-radiative multi-phonon entertainment from 4I11/2 to 4I13/2 degrees significantly reduces back-energy transfer and up-conversion losses caused by communication between Yb3+ and Er3+ ions excited at 2F5/2 and 4I11/2 degrees, respectively.
Basically, continuously, erbium-ytterbium-doped phosphate glass is pumped with wavelengths around the 975-nm absorption height of Yb3+ ions. That brings about the excitation of the ytterbium ions. Later, Yb ions may transfer the excitation power to surrounding erbium ions.
After an effective power transfer, one preliminary has an Er3+ ion in the 4I11/2 state (even more specifically, a Stark degree manifold), which has similar excitation power as the Yb3+ ions. From that state, the ions typically go through a quick non-radiative shift to the state 4I13/2, which is consistently used as the leading laser degree. Such non-radiative modifications take place based upon multi-phonon discharge, provided that the phonon power of the item is high and also adequate (which holds for silica fibers, as an example).
4) Application of Er, Yb: glass in Erbium glass laser
Er,Yb:glass is additionally an extraordinary item for upconversion luminescence. Laser got the eco-friendly and red laser from erbium-doped glass fiber, as well as individuals also observed violet upconversion light. The upconversion luminescence of Er:phosphate glass thrilled by Nd:YAG was checked out. The upconversion laser will certainly be truly useful in a wide variety of applications.
Er, glass is a pure three-level laser tool. As a result, it is necessary to pump almost all of the energetic glass aspects. The non-pumped areas are a source of laser light absorption losses. The non-pumped rod must be as short as possible in the case of the conventional post arrangement.
The optical excitation of the Yb,Er glass (specifically the chromium-free ones) happens mainly by utilizing Yb ions. The only Yb absorption band hinges on the near-infrared spectral array (900–1000 nm). Water discontinuation in this spectral range is 1 cm-1. Consequently, Er glass can drastically decrease the water-cooled laser’s efficiency because of pump light absorption in the water layer surrounding the flashlamp as well as the laser rod.
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