Ho³⁺/Yb³⁺-codoped germanate–tellurite glasses for 20  μm emission performance

Abstract

2.0 μm emission property of a new germanate-tellurite (GT) glass with Ho³⁺/Yb³⁺ codoping is synthesized and analyzed. Efficient 2.0 μm emission of Ho³⁺ ions sensitized by Yb³⁺ ions from the host glass was observed under 980 nm pumping. Based on the measured absorption spectra, the Judd-Ofelt parameters were calculated and discussed. The maximum emission cross section of Ho³⁺ ions transition is 4.36×10(-21) cm2 around 2.0 μm. The energy transfer efficiency is calculated and fitted the decay signals. The good spectroscopic properties suggest that Ho³⁺/Yb³⁺-codoped GT glass may become an attractive host for developing solid state lasers operating in the mid-infrared.

Broadband 2μm fluorescence and energy transfer evaluation in Ho3+/Er3+ codoped germanosilicate glass

“…It can be obtained that the peak emission cross section at 2 μm is as high as 5.18 Â 10 À 21 cm 2 . It is larger than that of silicate glass (3.54 Â 10 À 21 cm 2 ) [9], slightly lower than that of germanate glass (8.00 Â 10 À 21 cm 2 ) [21], and comparable to that of germanate-tellurite glass (4.36 Â 10 À 21 cm 2 ) [8]. High emission cross section makes the prepared germanosilicate glass an attractive candidate for 2 μm laser.…”

“…Emission cross section is an important parameter to estimate the possibility for achieving laser action. Higher emission cross section means that better laser gain can be achieved in glasses [8,36]. Emission cross section (σ em (λ)) at 2 μm can be calculated by Füchtbauer-Ladenburg (FL) equation [37] σ em ðλÞ ¼ λ 4 A rad…”

“…Ho 3 þ can not be pumped directly by readily available commercial high-power 808 nm or 980 nm laser diodes owing to the lack of an appropriate absorption band [1]. Hence, Yb 3 þ , Tm 3 þ , Nd 3 þ and Er 3 þ with a strong absorption band near 808 nm or 980 nm wavelengths have been utilized as the sensitizer to solve this problem [1,[8][9][10]. So far, Ho 3 þ /Yb 3 þ codoped [8,11,12], Ho 3 þ /Tm 3 þ codoped [13][14][15], and Ho 3 þ /Nd 3 þ codoped [1,16] glasses have been investigated by researchers.…”

“…Hence, Yb 3 þ , Tm 3 þ , Nd 3 þ and Er 3 þ with a strong absorption band near 808 nm or 980 nm wavelengths have been utilized as the sensitizer to solve this problem [1,[8][9][10]. So far, Ho 3 þ /Yb 3 þ codoped [8,11,12], Ho 3 þ /Tm 3 þ codoped [13][14][15], and Ho 3 þ /Nd 3 þ codoped [1,16] glasses have been investigated by researchers. However, to our knowledge, Er 3 þ sensitized Ho 3 þ doped glasses are less reported for 2 μm radiations but some investigations on upconversion and energy transfer process [10,17].…”

2 μm emission properties and nonresonant energy transfer of Er3+ and Ho3+ codoped silicate glasses

“…Moreover, Yb 3+ can be efficiently pumped by a laser diode (LD) near 980 nm which is one of the most popular and convenient commercial pump sources. So far, Ho 3+ /Yb 3+ codoped glasses131415 have been investigated by researchers. But, compared with Yb 3+ ions, Er 3+ : 4 I 13/2 level can match better with Ho 3+ : 5 I 7 level, which is more beneficial for 2 μm emissions16.…”