Broadband infrared emission from Er–Tm:Al2O3 thin films

Abstract

Thin films of amorphous aluminum oxide (Al2O3) co-doped with Er3+ and Tm3+ have been synthesized by alternate pulsed laser deposition. When pumped at 794 nm a broad emission band over 1400–1700 nm is observed. Two peaks related to the 1540 nm band from Er3+ and to the 1640 nm band from Tm3+ are clearly distinguished. The photoluminescence intensity ratio of the 1640–1540 nm emissions has been controlled by modifying the Tm concentration. A spectrum with a fairly flat profile and a full width at half maximum of 230 nm is obtained for an Er concentration of 7.2×1019cm−3 and a [Tm]∕[Er] concentration ratio of 3. It is found that the Er3+ to Tm3+ energy transfer processes play an important role in the definition of the luminescent response. The large width of the emission band and the excellent optical and thermomechanical properties of the Er–Tm co-doped Al2O3 signal this system as a potential candidate for the development of broadband integrated optical amplifiers.

Erbium‐doped integrated waveguide amplifiers and lasers

“…The optimum concentrations and doping ratio have been investigated theoretically [124,206,207,209,220], resulting in typical Yb:Er concentration ratios of 1:1 to 10:1. Besides Yb, other rare-earth co-dopants, such as Tm (1460-1530 nm, 1700-2100 nm) and Pr (1300-1400 nm), can be utilized for extending or adding additional amplification bandwidth [221].…”

Broadband near-infrared emission in Er^3+-Tm^3+ codoped chalcohalide glasses

“…However, silica and most silica-based glasses are not as suitable for Tm-gain devices as they are for Er ones. This is due to the fact that the transition Tm 3+ : 3 H 4 → 3 F 4 suffers appreciable multiphonon deexcitation because of the relatively high maximum phonon energy ͑1100 cm −1 ͒ of these glasses [1,3]. Therefore, the host matrix having low phonon energy to minimize multiphonon relaxation becomes essential.…”

“…2. A new strong emission at 1670 nm emerges in the case of the higher Tm 3+ concentration (G4), which can be assigned to the shortwavelength band-edge emission and corresponds to the electron transition of Tm 3+ from the 3 F 4 multiplet to the 3 H 6 multiplet [1,8]. Note that the peak emission for this band is centered at ϳ1840 nm, and its spectroscopic analysis was limited owing to the upper limit of the spectrometer at 1700 nm.…”

“…In common applications of erbium-doped silica-based amplifiers today, the characteristics of the erbium spectra have constrained the bandwidth of the spectra of the amplifiers. To improve this constraint, researchers look to multiple rare-earth (RE) ions codoping [1,2]. The Tm 3+ emission ( 3 H 4 → 3 F 4 transition) around 1470 nm allows a band extension in the spectral range corresponding to the S-band amplifier region, on the short wavelength side of the conventional Erdoped fiber amplifier C ϩ L bands at 1530-1570 nm [2].…”

Temperature-dependent photoluminescence spectra of Er–Tm-codoped Al2O3 thin film

“…Furthermore, the similarity of valency and lattice constant between Al 2 O 3 and Er 2 O 3 may allow incorporation of high concentration of Er into Al 2 O 3 crystal structure. Recently, much more attention has been paid to ErTm-codoped Al 2 O 3 thin films (Er:Tm:Al 2 O 3 ) at room temperature (RT), some results of which have been reported [6,7]. Nevertheless, deeper understanding of the mechanism of energy transfer (ET) processes from Er 3+ ions to Tm 3+ ions is required [6][7][8][9][10].…”