(1) What is an Er, Yb: phosphate glass?
The glass doped with Er as well as ytterbium ions is Er glass; Glasses doped with erbium, ytterbium, as well as chromium ions are additionally erbium glasses; the double adhered crystal of erbium glass and white glass is additionally erbium glass. The glass substrate in question is not common glass but phosphate glass. This paper mostly presents Er, Yb doped glass.
Er3+, Yb3+ co-doped phosphate glass (Er, Yb: phosphate glass) is a prominent as well as usually utilized energetic device for lasers producing in the “eye-safe” creepy series of 1,5-1,6 µm.
(2) What is phosphate glass?
Phosphate glass is a glass product that generally has phosphorus pentoxide (P2O5) and generally likewise contains other chemical components. It can be used as a laser gain tool in bulk and also fiber. Its major advantage is its high compatibility with rare-earth ions (see rare-earth-doped gain media), such as Erbium (Er3+), ytterbium (Yb3+), and also neodymium (Nd3+) ions. Simply put, the phosphate glass varieties can be doped with a high focus of laser-active rare planet ions without causing negative results such as clustering, which will create a quenching impact as well as influence the performance of the laser. The doping concentration in phosphate erbium-doped fiber is a lot more than that in quartz fiber, as well as it can increase by several percentage points.
The high doping focus of phosphate allows brief fiber lasers as well as amplifiers, which are not the only advantages of the glass but also consist of:
- The short fiber laser resonator can get a big totally free spectrum array, making it simpler to accomplish single-frequency procedure.
- Dispersed responses lasers are short, whereas extremely drugged phosphate fibers permit more efficient pump absorption.
- Ultrashort pulsed fiber lasers are less prone to nonlinear results if they use much shorter fibers.
(3) What’s the mechanism of erbium glass?
Phosphate glass combines a lengthy life time (~ 8 ms) of 4I13/2 Er3+ top laser degree with a reduced (2-3 ms) lifetime of 4I11/2 Er3+ level that remains to remain in resonance with Yb3+ 2F5/2 discharged up state. Quick non-radiative multi-phonon recreation from 4I11/2 to 4I13/2 level considerably decreases the back-energy transfer and also up-conversion losses due to the interaction between Yb3+ and also Er3+ ions, thrilled at the 2F5/2 together with the 4I11/2 degrees, specifically.
Essentially continually, erbium-ytterbium-doped phosphate glass is pumped with wavelengths around the 975-nm absorption elevation of Yb3+ ions. That causes the excitation of the ytterbium ions. Afterward, Yb ions might transfer the excitation power to surrounding erbium ions. After an effective power transfer, one preliminary has an Er3+ ion in the 4I11/2 state (far more especially, a Stark level manifold), which has comparable excitation energy as the Yb3+ ions. From that state, the ions generally undergo a quick non-radiative change to the state 4I13/2, consistently utilized as the leading laser degree. Such non-radiative modifications happen based upon multi-phonon discharge, gave that the phonon power of the item is high and appropriate (which holds for silica fibers, as an example).
(4) Application of Er, Yb: glass in Erbium glass laser
- Er, glass is also a phenomenal product for upconversion luminescence. Laser obtained the green and red laser from erbium-doped glass fiber, and also people also observed violet upconversion light. The upconversion luminescence of Er: phosphate glass delighted by Nd: YAG was checked out. The upconversion laser will certainly be truly functional in lots of applications
- Er, glass is a pure three-level laser device. As a result of this, it needs to pump nearly all the energised glass components. The non-pumped areas provide laser light absorption losses. In the case of the traditional pole arrangement, the non-pumped pole requires to be as brief as viable
- The optical excitation of the Yb, Er glasses (particularly chromium-free ones) occurs mostly making use of Yb ions. The only Yb absorption band depends on the near-infrared spooky array (900– 1000 nm). Water termination in this spooky range is 1 cm-1. Consequently, Er glass can substantially decrease the water-cooled laser performance due to pump light absorption in the water layer bordering the flashlamp as well as the laser rod.
