The document summarizes a student paper that proposes using a microring resonator system to generate tunable and storage potential wells for trapping and delivering bio-cells or molecules. The system utilizes the concepts of dark solitons and potential wells to introduce trapping forces. It consists of two microring resonators that allow a soliton pulse input to one to propagate and form a resonant output that becomes the input to the second microring resonator. The throughput field can then be controlled and stored by using the resonators, with amplified signals occurring between the left and right nanoring resonators. The technique could potentially be used for applications like transporting plant nutrients for feeding in a similar manner to drug delivery.

1. 2010 International Conference on Enabling Science and Nanotechnology (ESciNano),
1-3 December, 2010, KLCC, MALAYSIA
Student Paper
Tunable and Storage Potential Wells using Microring Resonator System
for Bio-cell Trapping and Delivery
N. Suwanpayaka, b, S. Songmuang<, M. A. Jalild, I. S. Amirid, I. Naimd, J. Alid and P. P. Yupapin*a
aAdvance Research Center for Photonics, Faculty of Science
King Mongkut 's Institute of Technology Ladkrabang Bangkok 10520, Thailand
bKing Mongkut 's Instilute of Technology Ladkrabang, Chumphon Campus 86160, Thailand
cFaculty of Science and Technology Kasem Bundit University, Bangkok 10250, Thailand
d
instilute of Advanced Photonics Science, ESciNano Research Alliance,
Universiti Teknologi Malaysia (UTM), 81300 Johor Bahru, Malaysia
.Email: kypreech@kmitl.ac.th
Bio cell manipulation is becoming area of importance and interesting. Meanwhile, the optical
technique manipulation has been widely used to uncover fundamental aspects of molecular and
biology [1]. In this work, we propose the technique that can be used to trap/delivery moleculeslbio
cell by using the concept of dark solitons and potential well, in which the trapping force is
introduced to manipulate the trapping tool. This optical technique has become a powerful tool for
manipulation of bio-molecules. It has the unique ability to manipulate matter mesoscopic scales
that has led to widespread application in biology [2].
Tunable and storage potential well can be generated by using an optical add/drop filter
incoperating two system that are microring resonators (MRRs) 1 and 2. Bio-cell or molecular cell
have driven by the optical trapping forces that acts on molecules can be obtained by the sum of the
gradient force and the scattering force (Ftrap = Fgrad + Fscat) .
Consider the trapping principle
F =
0
n
I 1281t5r6
(m2 -1
Jscat
C 3A4 m2 + 2 b
F = - � aVe =
_ n�r3
(m2 -1
JVE2grad
C 2 m2 - 2
To form the trapping potential (see Fig. 1), the input optical field (Einput) and the add port
optical field (Eadd) of the bright and bright solitons are introduced into the system and given by [4]
Ei"""' (t) � A sec h[�}Xp[(2�D
J-
ill,
t]
Ei"""' (t) � A tanh[�}Xp[(2�o
J-
ill.
t]
(1)
(2)
Where A and x are the optical field amplitude and propagation distance, respectively. T is a
soliton pulse propagation time in a frame moving at the group velocity, T = t - �l*X, where �1 and
�
2
are the coefficients of the linear and second-order terms of Taylor expansion of the propagation
constant. LD = T02/1�
2
1 is the dispersion length of the soliton pulse. To in equation is a soliton pulse
propagation time at initial input (or soliton pulse width), where t is the soliton phase shift time,
and the frequency shift of the soliton is 000. This solution (i.e. Eq. 1.) describes a pulse that keeps
its temporal width invariance as it propagates, and thus is called a temporal soliton .When a
soliton peak intensity (1�
2
/ rxT021) is given, then To is known. When a soliton pulse is propagated
within a nonlinear microring device, a balance should be achieved between the dispersion length
(LD) and the nonlinear length (LNL = lIr�Nd, where r = n
2
*ko, is the length scale over which
dispersive or nonlinear effects makes the beam become wider or narrower. For a soliton pulse,
there is a balance between dispersion and nonlinear lengths, hence LD= LNL.
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2. 2010 International Conference on EnablingScience and Nanotechnology (ESciNano),
1-3 December,2010,KLCC,MALAYSIA
When light propagates within the nonlinear material (medium), the refractive index (n) of
light within the medium is
n=no+n21=no+�P (3)
AefT
where no and n2 are the linear and nonlinear refractive indexes,respectively. I and P are the optical
intensity and optical power,respectively. The effective mode core area of the device is given by
Aerr. For the series microring resonator (MRRs),the effective mode core areas range from 0.50 to
0.10 11m
2
[2]. When a soliton pulse is input and propagated within a MRR,as shown in Fig.l,
which consists of a series MRRs. The resonant output is formed,thus,the normalized output of
the light field is the ratio between the output and input fields [Eout(t) and Ein(t)] in each roundtrip,
which is
I
EoutCt)12
= C1-)1- C1-C1-Y)X2)K l
EinCt) 1 C1-x�1-yJ1-K)2+4X�1-yJ1-Ksin2C�)J
(4)
The close form of Eq. (4) indicates that a ring resonator in this particular case is very similar to a
Fabry-Perot cavity,which has an input and output mirror with a field reflectivity,(l-K),and a
fully reflecting mirror. K is the coupling coefficient,and x=exp(-aL/2) represents a roundtrip loss
coefficient, �o=kLno and �NL=kLn2IEii are the linear and nonlinear phase shifts,k=27t/A is the
wave propagation number in a vacuum,where L and a= 0.5 dBmm-I are waveguide length and
linear absorption coefficient,respectively. The fractional coupler intensity loss is y = 0.1. neff is
the effective refractive index of the waveguide,and the circumference of the ring is L=27tR,with
R as the radius of the ring. In operation,the soliton pulse is input and propagated within a micro
ring resonator as shown in Fig.l. The system consists of a series of micro ring resonator,whereas
the resonant output is formed and become soliton input into MRR2. The throughput field will be
controlled,i.e. stored and tuned,in which the amplified signals are occurred by using the right and
left nanoring resonators (RR and Rd. In application, the proposed technique can be used to
transport the plant food feeding within the same way of drug delivery.
References
[1] R. Yang,1. Cecil,L. Zhang,N. Gobinath, "A semantic web based framework for bio cell
manipulation," Proceedings o/the 3rd Annual IEEE Coriference on Automation Science and
Engineering Scottsdale, AZ,USA,Sept 22-25,2007.
[2] C. Teeka and P. P. Yupapin,"Hybrid Interferometer using dynamic optical tweezers," Nano
Communication Networks, 2010.
[3] G. T. Roman, Y. Chen and P. Viberg, "Single-cell manipulation and analysis using
microfluidic devices," Anal. Bioanal Chem., vol. 387,pp. 9-12,2007
[4] P. P. Yupapin,1. Ali, "Photon trapping with a nano-ring resonator controlled by light," Optik,
2009.
,,-----------------------......,I I
I
I
I
E
I
input!
I
�rRR SySIt'1li I.
' ,----------------------- -,
EdzOp
I
I
I E output
I
I ,--------------- ...
,--- ----- ------- -'
I
I
I
E through
Fig. 1. Schematic diagram of ring resonator system,where the MRR1 and MRR2 consist of R1 and
R2, Ro= 300 nm,RR= 30 nm and RL= 30 nm radii
ESciNano 2010 - http://www.ike.utm.my/mine/escinan02010