Generation of arbitrary vector beams based on a
single spatial light modulator and a thin-film
polarization splitting cubic
Yiyan Xie (谢一言), Yang Yang (杨杨), Lu Han (韩 璐), Qingyang Yue (岳庆炀),
and Chengshan Guo (国承山)*
College of Physics and Electronics, Shandong Normal University, Jinan 250014, China
*Corresponding author: guochsh@sdnu.edu.cn
Received September 8, 2016; accepted October 28, 2016; posted online November 25, 2016
A setup for the generation of arbitrary vector beams is proposed. The setup mainly consists of a spatial light
modulator (SLM), an angle-adjustable polarization beam splitter modulator, and a spatial filtering imaging
system. Compared with the system using a birefringent beam splitter with a non-adjustable splitting angle,
the polarization splitting angle of the improved setup can be adjusted by slightly rotating the related mirrors,
which will bring more convenience when different wavelengths and different pixel sizes of SLMs are involved.
The experimental results also demonstrate that the setup possesses a good polarization-selective imaging
ability, which reveals that the setup may also be useful in polarization-selective spatial filtering imaging
and polarization-encoded encryption.
OCIS codes: 260.5430, 230.5440, 090.1760.
doi: 10.3788/COL201614.122601.
Vector beams are usually reserved for beams with a non-
uniform distribution of polarization states in space
[1]
.A
radially polarized beam is the prime example of vector
beams. In recent years, vector beams have attracted much
attention in many research fields due to their unique prop-
erties
[1–5]
in contrast to beams with a uniform distribution
of polarization states. A lot of progress has been reported
in exploring new optical effects of vector beams and their
applications in various scientific and engineering realms
such as focus shaping
[5–8]
, surface plasmon excitation
[9,10]
,
optical trapping
[11–14]
, and laser material processing
[15,16]
.
Many methods for transforming a conventional scalar
laser beam into a vector beam with the desired polariza-
tion distributions have been reported in recent years,
which can be clarified into static
[17–24]
and dynamic
[25–38]
ap-
proaches. The former mainly adopted specially designed
laser resonators and polarization-selective micro-optical
structures. For example, in Refs. [
23,24] the vector beams
were generated by means of manipulating the local orien-
tation and geometric parameters of the metasurfaces. The
latter are mainly based on programmable spatial light
modulators (SLMs), which have the advantage of provid-
ing dynamic and programmable modulations. Since the
complete control of a vector beam generally requires inde-
pendent modulation of the complex amplitudes in two
orthogonal polarization states, the methods reported in
Refs. [
25–27] utilized two separate SLMs for that purpose,
while the methods in Refs. [
28–38] mainly relied on a
single SLM in combination with some specially designed
optical paths or elements for polarization splitting and
recombination.
Recently we reported a simple system for the generation
of arbitrary vector beams based on a small-angle birefrin-
gent beam splitter (BBS)
[39]
. Although the introduction of
the birefringent crystal in this method can greatly simplify
the system and improve the quality of the generated
vector beams, it also brings some disadvantages when dif-
ferent wavelengths or ultrashort pulse beams are involved.
For example, the birefringent crystal will result in an
obvious optical path difference between the two polariza-
tion components because of the refractive index change of
the birefringent crystal from its vertical axis direction to
the parallel axis direction; in addition, the splitting angle
of the BBS is also wavelength dependent because of the
dispersion properties of the birefringent crystal. In this
Letter, we propose another setup for the generation of
arbitrary vector beams. We designed a small-angle angle-
adjustable polarization beam splitter (APBS) based on a
commonly used thin-film 90° polarization splitting cubic
(PSC) and adopted it to replace the BBS in the system
for generating arbitrary vector beams. The improved sys-
tem may have a more extensive application range because
of having avoided the use of the BBS.
It is known that a vector beam on a plane perpendicular
to the optical axis can be generally decomposed into two
orthogonal polarization components u
x
ðx; yÞ and u
y
ðx; yÞ.
Using the Jones vector representation, the vector beam
can be expressed as
~
E ¼
u
x
ðx; yÞ
u
y
ðx; yÞ
¼
A
x
ðx; yÞe
jφ
x
ðx;yÞ
A
y
ðx; yÞe
jφ
y
ðx;yÞ
; (1)
where (A
x
ðx; yÞ, A
y
ðx; yÞ) and (φ
x
ðx; yÞ, φ
y
ðx; yÞ) are,
respectively, the amplitudes and phase distributions of
the two polarization components. Obviously, four degrees
of freedom are necessary in order to fully characterize
a vector beam, and an ideal vector beam generator
COL 14(12), 122601(2016) CHINESE OPTICS LETTERS December 10, 2016
1671-7694/2016/122601(5) 122601-1 © 2016 Chinese Optics Letters