讲义下载II

Report
硅光子学中的光源问题
冉广照
[email protected]
北京大学物理学院
介观物理国家重点实验室
2012.07. 04
SPP Excitation
Other?
Outline
I.
Surface Plasmons
II.
Electrical Surface Plasmon
III.
Plasmon Laser
直接电激发示意图例
A Pioneering work
Nat Mater 9, 21 ( 2010)
D. M. Koller et al Nat. Photonics 2, 684,2008.
真空中偶极子辐射
pμ e
 i t
偶极子辐射的空间分布
近场区,过渡区,远场
S 
偶极子的阻尼受迫振动
2
d p
dt
2
 b0
dp
dt
 0 p 
2
sin
R
e
2
m
E
2
θ 
n
2
空间中的TM波
非自由空间偶极子模型
z
dipole
1
d

2
有界面时的偶极子辐射场
当然也可写出K空间的分布
k 空间偶极子功率谱的推导
Power dissipated by the dipole
振荡偶极子引起的电流
k 空间电场表示及电场积分形式

k  (k   ) 
Ek 
exp[  i k z ( d )
 
2
2 
2
2  1 
k - k 1 

-1



k  k //  k z
Dipole 所在介质1中
2
2 1/ 2
q 1  ( k 1  k // )

, Im( q 1 )  0
把kz 积分掉


k  (k   ) 
E (r) 
d k // exp( i k //   )  d k z   
exp[ ik z ( z  d )]
2
2 
2

2  1
--kkzz2-q-12q 1 


-1
k 空间偶极子功率谱

i k //  
dk //


2 1
k1
 dk
0
k //
//
q1
[ k //   
2
2
1
2
( k 1  q 1 )  // ]
2
2
2
均匀介质中偶极子k 空间功率谱
kz
1
k1
dP
k
k//



k  k //  k z
Free space
p free dk //
横轴坐标归一化
k // / k 1
金属界面附近的偶极子
考虑到金属界面的反射:
dipole z
d

1
2
Ag
E tot (r)  E(r)  E R (r)
原电场
反射场
k// p
金属界面附近的偶极子
k1
P 
 dk
0
dP
//
d k //
依据各种模式的波矢的平行分量的大小
金属界面附近的偶极子
dipole
d
k1
z
1
x
dP
2
p free dk //
k /k
Ag
金属上面有介质薄膜的情况
金属上面有介质薄膜的情况
k1
dP
p free dk //
k // / k 1
结构中的发光体
Superstrate mirror
θ
ki=kz+k//
k//,
Region 3
rs13, rp13
Region 1
t
AlQ
b
rs12, rp12
Region 2
Substrate mirror
J. Lightwave Techn. 17 2170 (1999)
Reflectivity/transmission coefficient
• Characteristic matrix of an optical film
 cos( k 0 nz cos  )  ( i / p ) sin( k 0 nz cos  ) 
M  
,
cos( k 0 nz cos  )
  ip sin( k 0 nz cos  )

N
M 

Mi
For TE wave, (s-polarized) ;
p


cos 
M2
M1
i 1
r s
( m 11  m 12 p out ) p in  ( m 21  m 22 p out )
( m 11  m 12 p out ) p in  ( m 21  m 22 p out )
q 
u

cos 
, ts 
2 p in
( m 11  m 12 p out ) p in  ( m 21  m 22 p out )
for TM wave,(p-polarized, p is replaced by q.
Born & Wolf, Principles of Optics
Power dissipation spectrum
• I(k//)
ki=nik0;
J. Lightwave Techn. 17 2170 (1999)
Power dissipation spectrum
Air
DBRSPP
Gl
b, 发光分子辐射功率

b
b0, 发光体在自由空间的辐射功率
 1  q  q  I ( k // ) dk //
0
q, 发光分子的辐射复合效率
b0
k// 面内波矢分量
b iso
2 b // 1 b 
I(k//) 对应于k//的功率密度


J. Lightwave Techn. 17 2170 (1999)
b0
3 b0
3 b0
应用
调控自发辐射,优化器件结构
设计SPP 发光管 和 SPP激光
结构对能量耗散谱的影响
Surface plasmon –enhanced PL of
nano-Si
Surface plasmon –enhanced EL
增强3倍
Electrical Excitation of Confined SPP
in Metallic Slot Waveguides
couple light
emitted by the
LED directly into
waveguided
plasmon modes.
Pol,
Decay,
Spectra
Nano Letters10,
1429 (2010)
Gain-assisted propagation of SPP via
electrically pumped quantum wells
(a) InGaAsP QW controlled
SPP waveguides
(b) Calculated material
gain at around 1:55 μm of threelayer InGaAsP QWs for different
carrier densities
OPTICS LETTERS 35,3075(2010)
OLED as Electric SPP Source/WG
Surface Plasmon Polariton (SPP)
x (TM)
z
Au
organic
silicon
SPP
waveguide
Source
waveguide
y (TE)
WG
Si-OLED is naturally a SPP source
and waveguide (WG)
source
p-Si / NPB 60 nm / CBP: Irpiq3
45 nm / Bphen:Cs2CO3 15 nm
/Sm /Au
Some Pioneering work
Organic plasmonic diode
D. M. Koller et al Nat. Photonics 2, 684,2008.
Our Work on Si-organic SPP source
Ordinary OLED with Si anode
Edge emission
Polarized Electroluminescence
(EL) observed
p-Si / NPB 60 nm / CBP:
Irpiq3 45 nm /
Bphen:Cs2CO3 15 nm
/Sm 5 nm /Au 30 nm
Ran, et,al, Appl. Phys. Lett. 97, 233304 (2010)
Surface Vs Edge (emission)
x (TM)
Surface-emission
z
Edge-Emission
y (TE)
y
x™
z
YTE
Au-cathode OLED on Si
Si-OLED as Electric SPP Source/WG
air
org
SPP
Spontaneous
Power dissipation spectra
SPP source
Ag-cathode (Si-OLED)
TM field
TE field
Ag-QW Schottky Plasmonic diode
OPTICS EXPRESS 20 , 8710 (2012)
Next work
High efficiency and suitable wavelength
SPP Laser

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