Room Temperature Continuous-wave Operation of Two-dimensional Photonic Crystal Nanolasers
Yu-Chen Liu 1,2 (劉育辰 ), Yi-Chun Yang 1(楊怡君 ), Zi-Chang Chang 2(張子倉 ), M. C. Wu 2(吳孟奇 ) and M. H. Shih 1,3 (施閔雄 ) 1Research Center for Applied Science (RCAS), Academia Sinica, Taiwan. 2Department of Electrical Engineering, National Tsing Hua University , Taiwan. 3Department of Photonics, National Chiao Tung University, Taiwan. Address: 128 Sec.2, Academia Rd., Nankang, Taipei 11529, Taiwan Phone : 03-5712121 ext.59470, Fax : 03-5745233, Email : [email protected]
Abstract : Photonic crystal nanolasers had been fabricated on a sapphire substrate. The room temperature continuous-wave (CW) lasing near 1550 nm had been achieved.
Motivation
Fabrication
PMMASiNx
InGaAsP
Sapphire
PMMASiNx
InGaAsP
Sapphire
SiNxInGaAsP
Sapphire
InGaAsP
Sapphire
E-beam lithography
ICPRIE
Summary We have demonstrated the D1 and point-shift sapphire-bonded photonic crystal nanolasers under CW operating conditions at room temperature. The CW nanolasers has ultrasmall size, excellent heat dissipation and low threshold. It is very useful for
D1 here means one hole was removed from the hexagon photonic crystal
D1 CW photonic crystal nanolaser on sapphire
Point-shift here means shifts of two lattice points to form the defect cavity, like ( a ).
Point-shift CW photonic crystal nanolaser on sapphire
The structure can only lase under pulsed condition.
Thermal conductivity
Air : 2.5×10-5 W/cm K‧
The structure can lase under CW condition.
Thermal conductivity
Sapphire : 5×10-1 W/cm K‧
In the fabrication, first the InGaAsP wafer are bonded with the sapphire wafer , the following process are showed in the following flow charts :
lattices to form a defect cavity.
This is the smallest photonic crystal cavity on the substrate so far.
mode volume
0.023μm3 ~1.5(λ/2n)3
500 nm
~580 nm
mode volume
0.014μm3 ~1.15(λ/2n)3
500 nm
200nm
300nm
a d
d
r
a = lattice constant
r = radius
d = shifts of lattice points
SEM image (Top view) SEM image (angle view) FDTD simulated mode profile
Lasing spectrum (CW) under room temperature
Light-in light-out curve (LL-curve)
Lasing wavelength vs lattice constant
SEM image (Top view) SEM image (angle view) FDTD simulated mode profile
Lasing spectrum (CW) under room temperature
Light-in light-out curve (LL-curve)
Lasing wavelength vs lattice constant
Nanocavity with about 580 nm in diameter
High side-mode suppression-ratio , which is over 20 dB
Low threshold 0.85 mW, but after estimating the material absorption, surface reflectivity of the cavity structure, the effective threshold power
Smallest CW laser on the substrate
Ultrasmall mode volume, only 0.014μm3
The effective threshold power is only 40 μW after estimating the material absorption, surface reflectivity of the
future dense integrated photonic circuits.
cavity structure
is only 35 μW
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