Realization of a continuous frequency-tuning Ti:sapphire
laser with an intracavity locked etalon
Xuejun Sun (孙雪俊), Jiao Wei (魏 娇), Wenzhe Wang (王文哲),
and Huadong Lu (卢华东)*
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics,
Shanxi University, Shanxi 030006, China
*Corresponding author: luhuadong@sxu.edu.cn
Received April 8, 2015; accepted April 29, 2015; posted online June 1, 2015
A continuous-wave all-solid-state tunable Ti:sapphire laser with compact configuration is presented. The
frequency-tuning range extends from 760 to 825 nm by rotating the birefringent filters. When the intracavity
etalon is locked on the oscillating frequency of the laser and the length of the resonator is scanned by the piezo-
electric ceramics transducer, a maximal continuous frequency-tuning range of 15.3 GHz is realized. The obtained
Ti:sapphire laser is successfully applied to scan the saturation absorption spectroscopy of D
1
transitions of
87
Rb
atoms around the wavelength of 794.97 nm.
OCIS codes: 140.3590, 140.3600, 140.3570, 140.3560.
doi: 10.3788/COL201513.071401.
All-solid-state continuous-wave (cw) tunable Ti:sapphire
lasers with single-frequency operation have been widely
applied to spectroscopic measurements, quantum commu-
nication, laser radar, and so on owing to their character-
istics of high conversion efficiency, broad tuning range,
and good beam quality
[1]
. Since the first single-frequency
Ti:sapphire laser was demonstrated in 1988
[2]
, much atten-
tion
[3–5]
have been focused on its high output power
[6]
,
small frequency drift
[7]
, and low-intensity noise
[8]
. Re-
cently, many experiments require a Ti:sapphire laser with
continuous frequency-tuning ability. For example, in an
experiment of cooling atoms, it is important to be able
to precisely control the frequency of the lasers correspond-
ing to the absorption line of the atoms, which is applied
in quantum information protocols to implement quantum
storage
[9]
. Three commercial versions of continuous
frequency-tuning Ti:sapphire lasers have been supplied
by Coherent
[10]
, Spectra-Physics
[11]
, Tekhnoscan Joint-
Stock
[12]
companies. In all these laser products, the length
of the resonator is sufficiently long that they had to insert
other tuning elements to realize continuous frequency-
tuning, which will introduce extra loss and decrease
the optical conversion efficiency. Another version of the
Ti:sapphire laser supplied by M-square company
[13]
is
compact, but the matched pump source with multi-
longitudinal-mode operation increases its intensity
noise
[14]
, which limits the application of the Ti:sapphire
laser. In 2014, we obtained a single-frequency Ti:sapphire
laser with a continuous frequency-tuning range of 48 GHz
by inserting a nonlinear crystal into the resonator which
was composed of six mirrors
[15]
. On this basis, a compact
Ti:sapphire laser with continuous frequency-tuning by
means of an intracavity locked etalon is reported in this
Letter. The adopted length of the resonator is sufficiently
short that it is not necessary to insert other tuning
elements into the cavity to tune the frequency of the laser
and only scanning the piezoelectric transducer (PZT)
adhered to the cavity mirror is enough to achieve a broad
frequency-tuning range of the Ti:sapphire laser.
The experimental setup of the continuous frequency-
tuning Ti:sapphire laser with intracavity locked etalon
is shown in Fig.
1. The pump source is a homemade
cw single-frequency and frequency-doubled Nd:YVO
4
laser with the output power of 11 W at the wavelength
of 532 nm (F-VIII B, Yuguang Co., Ltd)
[16]
. The pump
532 nm laser is coupled into the Ti:sapphire ring cavity
and focused onto the Ti:sapphire crystal by a coupling sys-
tem including f
1
(f ¼ 200 mm) and f
2
(f ¼ 120 mm). A
half-wave plate (HWP) in front of the resonator is used
for the polarization alignment of the pump laser with re-
spect to the optical axis of the Ti:sapphire crystal. The
resonator of the Ti:sapphire laser, which has a ring-type
configuration for the prevention of spatial hole burning,
is composed of two curved mirrors with a 100 mm radius
of curvature [M1 and M2, both coated with high-reflection
Fig. 1. Schematic diagram of the continuous frequency-tuning
Ti:sapphire laser.
COL 13(7), 071401(2015) CHINESE OPTICS LETTERS July 10, 2015
1671-7694/2015/071401(4) 071401-1 © 2015 Chinese Optics Letters