Optically induced atomic lattice with tunable
near-field and far-field diffraction patterns
FENG WEN,
1,2,†
HUAPENG YE,
2,†
XUN ZHANG,
1
WEI WANG,
1
SHUOKE LI,
1
HONGXING WANG,
1,
*
Y
ANPENG ZHANG,
1
AND CHENG-WEI QIU
2
1
Key Laboratory for Physical Electronics and Devices of the Ministry of Education & School of Science & Shaanxi Key Laboratory
of Information Photonic Technique & Institute of Wide Bandgap Semiconductors, Xi’an Jiaotong University, Xi’an 710049, China
2
Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
*Corresponding author: hxwangcn@mail.xjtu.edu.cn
Received 11 August 2017; revised 3 October 2017; accepted 4 October 2017; posted 5 October 2017 (Doc. ID 304051);
published 8 November 2017
Conventional periodic structures usually have nontunable refractive indices and thus lead to immutable photonic
bandgaps. A periodic structure created in an ultracold atoms ensemble by externally controlled light can overcome
this disadvantage and enable lots of promising applications. Here, two novel types of optically induced square
lattices, i.e., the amplitude and phase lattices, are proposed in an ultracold atoms ensemble by interfering four
ordinary plane waves under different parameter conditions. We demonstrate that in the far-field regime, the atomic
amplitude lattice with high transmissivity behaves similarly to an ideal pure sinusoidal amplitude lattice, whereas
the atomic phase lattices capable of producing phase excursion across a weak probe beam along with high trans-
missivity remains equally ideal. Moreover, we identify that the quality of Talbot imaging about a phase lattice is
greatly improved when compared with an amplitude lattice. Such an atomic lattice could find applications in all-
optical switching at the few photons level and paves the way for imaging ultracold atoms or molecules both in the
near-field and in the far-field with a nondestructive and lensless approach.
© 2017 Chinese Laser Press
OCIS codes: (050.0050) Diffraction and gratings; (270.1670) Coherent optical effects; (050.5080) Phase shift; (070.6760) Talbot and
self-imaging effects.
https://doi.org/10.1364/PRJ.5.000676
1. INTRODUCTION
In the past few years, artificial periodic structures, such as pho-
tonic crystals [1–5] and metamaterials [6–9], have attracted
increasing attention due to their unprecedented capacities of
engineering the transmission and reflection properties of waves.
An important property of such applications is the ability to
strongly modify the propagation of light in certain directions
and frequencies. A number of new physical phenomena have
been predicted to occur in these materials, including strong
localization of light [10], inhibited spontaneous emission from
atoms [11], photon– atom bound states [11], all-optical signal
processing, and switching [12].
Conventionally, photolithography and electron beam
lithography are widely used to fabricate the periodic structures
with microsized or nanosized features. However, the refractive
index of the resulting periodic structures is usually nontunable,
thus leading to immutable photonic bandgap (PBG). To fully
explore the potential of photonic crystals, it is crucially impor-
tant to achieve a dynamical tunability of their bandgap [13].
In previou s studies, a distinct approach to generate spatially
periodic structures, based on the electromagnetically induced
grating (EIG) [14], is proposed by Ling et al. [15] and exper-
imentally demonstrated in cold [16] and hot [17] atomic sam-
ples. Very recently, the spatially dependent electromagnetically
induced transparency (EIT) in cold atoms was demonstrated by
using the phase profile as a control parameter for the atomic
opacity [18]. Unlike traditional photonic crystals, here a peri-
odic structure is created by externally controlled light, and a
novel photonic structure with an optically tunable PBG is
achieved [19]. The EIG with tunable first-order diffraction
has attracted considerable interest due to its potential applica-
tions in all-optical switching and routing [17], light storage
[20], probing optical properties of materials [21], optical bista-
bility [22], shaping a biphoton spectrum [23], and beam split-
ting and fanning [24]. However, 2D EIG and its diffraction
pattern in near-field and far-field have not been demonstrated
yet. In this paper, we demonstrate that optical lattices resulting
from amplitude modulation and phase modulation can be real-
ized in an ultracold atoms ensemble by interfering four ordinary
plane waves under different parameter conditions. We analyze
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Vol. 5, No. 6 / December 2017 / Photonics Research
Research Article
2327-9125/17/060676-08 Journal © 2017 Chinese Laser Press