Continuous-wave laser operation at 743 and 753 nm based on a diode-
pumped c-cut Pr:YAlO
3
crystal
Xiuji Lin
a
, Xiaoxu Huang
a
, Bin Liu
c
, Bin Xu
a
,
*
, Huiying Xu
a
, Zhiping Cai
a
,
Xiaodong Xu
b
,
**
, Dongzhen Li
b
, Jian Liu
b
, Jun Xu
c
a
Department of Electronic Engineering, Xiamen University, Xiamen 361005, China
b
Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116 ,
China
c
School of Physics Science and Engineering, Institute for Advanced Study, Tongji University, Shanghai 200092, China
article info
Article history:
Received 1 October 2017
Accepted 8 December 2017
Available online 14 December 2017
Keywords:
Blue diode pumped
Pr:YAP crystal
Continuous-wave laser
Polarized laser
abstract
We report on blue-diode-pumped continuous-wave Pr:YAlO
3
(YAP) crystal lasers. Using a b-cut sample, a
maximum output power of 181 mW is achieved at ~747 nm with slope efficiency of 12.7% with respect to
the absorbed power. Using a c-cut sample, a dual-wavelength laser at ~743 and ~753 nm is obtained with
a total maximum output power of 72 mW by using the blue diode pumping, for the first time to our
knowledge. These laser emissions are all linearly polarized and M
2
factors of these output laser beams
are also measured. YAP is experimentally verified to be one of effective oxide hosts for Pr-doped visible
laser operation besides its fluoride counterparts.
© 2017 Elsevier B.V. All rights reserved.
1. Introduction
During the past decade, praseodymium ions (Pr
3þ
) laser emis-
sions at visible have attracted much attention and developed
greatly based on solid-state laser technology, which can be effec-
tively excited to pumping level by blue photons [1e3]. On the one
hand, potential and practical applications with respect to visible
lasers, such as color display, remote sensing and data storage, have
motivated researches on visible lasers [4,5]. On the other hand,
although in the development of Pr
3þ
lasers several sources were
used to pump Pr
3þ
ions, e.g. argon-ion laser [6], flash lamp [7],
optically pumped semiconductor lasers (OPSLs) [8,9] and
frequency-doubled solid-state laser at 469 nm [10,11], InGaN blue
diode laser is still the most suitable pump source for Pr
3þ
lasers
because of their compactness, commercial availability and accept-
able price. Fortunately, during the past decade, InGaN diode laser
have gained great development, which promotes the development
of Pr
3þ
lasers.
In comparison to fluorides, oxide laser materials in general
exhibit good thermal and mechanical properties, which favor
power scaling especially for diode-pumped solid-state lasers in
longitudinally pumping geometry. Up to now, only two Pr-doped
oxides have been experimentally demonstrated to be effective for
visible laser emissions, i.e. Pr
3þ
,Mg
2þ
:SrAl
12
O
19
[12] and Pr:YAP
[13e15]. In this work, we have focused on the latter because YAP is
an attractive laser host with good thermal and mechanical prop-
erties as above mentioned. Moreover, YAP is almost the most
investigated biaxial material, which possesses different polariza-
tion properties in three orthogonal directions, thus leading to
polarized laser emissions and relatively more abundant lasing
possibilities than isotropic and uniaxial matrices. Specifically for
YAP, its Mohs hardness is between 8.5 and 9, while fluorides are
about 4 in general. The thermal conductivity of YAP is about 11 W/
m/K at 300 K, close to YAG. As an excellent candidate, in fact, YAP
has once been doped with various rare earth ions for laser gener-
ations, such as Nd
3þ
[16,17],Tm
3þ
[18],Er
3þ
[19] and Ho
3þ
[20].
In terms of Pr:YAP visible lasers, at present, using InGaN as
pump source, continuous-wave lasing has been investigated but
only in b-axis cut of the Pr:YAP sample, i.e. only lasing at E//a or E//c
polarizations. E//b polarization has not yet been studies, to our
knowledge. In fact, in early 1994, E//b polarized laser operation of
Pr:YAP was indeed demonstrated but with a low-efficiency and
cumbersome argon ion laser as pump source. Additionally, the
output power of the E//b polarized lasers was far limited to less
than 1 mW [21].
* Corresponding author
** Corresponding author.
E-mail addresses: xubin@xmu.edu.cn (B. Xu), xdxu79@mail.sic.ac.cn (X. Xu).
Contents lists available at ScienceDirect
Optical Ma terials
journal homepage: www.elsevier.com/locate/optmat
https://doi.org/10.1016/j.optmat.2017.12.016
0925-3467/© 2017 Elsevier B.V. All rights reserved.
Optical Materials 76 (2018) 16e20