Browsing by Author "Lu, Tsan-Wen"

Now showing 1 - 20 of 42

1D photonic crystal strain sensors
(2018-07-01)
Lu, Tsan-Wen
;
Wu, Chia-Cheng
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
We introduce a photonic crystal nanocavity consisting of one-dimensional periodic nanorods embedded in a deformable polydimethylsiloxane substrate, which exhibits a high-quality factor and a large wavelength response to the applied strain. By further investigating its wavelength response to nonaxial planar strains, we propose and experimentally demonstrate a sensor unit that can precisely identify different planar strains, including their application direction, type, and value. This sensor prototype with small footprint and feasible coupling with optical waveguides could provide additional flexibility for strain analysis in a wide range of fields.
Compressible 1D photonic crystal nanolasers with wide wavelength tuning
(2017-06-15)
Lu, Tsan-Wen
;
Wu, Chia-Cheng
;
Wang, Chun
;
Lee, Po-Tsung
;
資訊工程學系
We propose and demonstrate a tunable photonic crystal nanolaser consisting of 1D periodic nanorods wrapped in deformable polydimethylsiloxane. In addition to low-threshold and long-term lasing stability, the nanolaser also displays reproducible and reliable wavelength tuning with a large tunability of 7.7 nm under 1% compression. By further associating with stretching, a very wide wavelength-tunable range of 155 nm that almost spans the entire S + C + L telecommunication bands is successfully demonstrated with a single nanolaser device. (C) 2017 Optical Society of America
Dielectric-Band Photonic Crystal Nanobeam Lasers
(2013-01-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Chiu, Li-Hsun
;
交大名義發表
;
光電工程學系
We investigate a mode gap confined dielectric band laser via a 1-D photonic crystal (PhC) nanobeam (NB) nanocavity with lattice gradually shifted PhC mirror. Owing to different modal symmetries, different zeroth-order dielectric mode properties, including quality (Q) factors, mode volumes, lasing thresholds, and slope efficiencies, in nanocavities with two different cavity sizes are investigated. In experiments, single-mode lasing from dielectric bands with low effective lasing thresholds is obtained. Rising of the high-order modes is also observed when we increase the PhC mirror periods for high Q factor of the zeroth-order dielectric mode. In addition, we observe the bonding and antibonding modes in beamwidth mismatched coupled NB nanocavities and switch the dominant lasing mode via spatially nonuniform carrier injection.
Driving Lightwave in Nanopatterned Nanowire
(2015-01-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
光電工程學系
;
Department of Photonics
Engineering surface lattice resonance of elliptical gold nanodisk array for enhanced strain sensing
(2018-12-10)
Chang, Kai-Hao
;
Cheng, Jiunn-Shouh
;
Lu, Tsan-Wen
;
Lee, Po-Tsung
;
光電工程學系
We demonstrate an elliptical gold nanodisk array (GNA) for engineering the spectral profile of surface lattice resonance (SLR). The nanodisk's shape has a great impact on SLR. A small linewidth of 20 mn at an aspect ratio of 1.17 and a large wavelength tuning of 64 nm within 4% strain via different orientations and polarizations is achieved experimentally. The enhanced wavelength response of 6.93 mu per 1% strain variation for elliptical GNA is 2.4 times better than that for general circular GNA. Furthermore, figure of merit of strain sensing for elliptical GNA approaches 5.7 times greater than that for circular GNA. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Gold Bowtie-Shaped Dimer Arrays in a Stretchable Substrate with Tunable LSPR
(2018-12-01)
Lu, Tsan-Wen
;
Chen, Peng-Yu
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
We proposed and demonstrated a gold bowtie-shaped dimer array semi-buried in a deformable polymer substrate. The wavelength tunability of coupled bonding localized surface plasmon resonance modes with different polarizations was confirmed by stretching simulations and experiments. The tuning operations were reconfigurable and reliable under applied elongations of up to 50%.
High quality factor circular photonic crystal microcavity lasers
(2007)
Lu, Tsan-Wen
;
Fan, Jyun-Hao
;
Tsai, Feng-Mao
;
Lee, Po-Tsung
;
光電工程學系
The isotropic photonic bandgap (PBG) with only 6.7% width variation of circular photonic crystal (CPC) is investigated by finite-difference time-domain (FDTD) method. Whispering gallery mode (WGM) is sustained in CPC microcavity from FDTD simulation. The WGM single-mode lasing with low threshold (similar to 0.13 mW) and high quality (Q) factor (> 10000) is obtained from well-fabricated devices.
High quality factor microcavity lasers realized by circular photonic crystal with isotropic photonic band gap effect
(2007-04-09)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Fan, Jyun-Hao
;
Tsai, Feng-Mao
;
光電工程學系
The photonic band gap (PBG) effect and its isotropy of sunflower-type circular photonic crystal (CPC) are obtained and investigated from the transmission spectra performed by finite-difference time-domain (FDTD) method. The PBG directional width variation is found to be only 6.7%. A well-confined whispering gallery mode (WGM) with azimuthal number of 6 is obtained by FDTD simulation from the CPC microcavity formed by seven missing air holes (C2). Ascribed to the deep and isotropic PBG confinement, the WGM lasing with very-low threshold (similar to 0.13 mW) and very-high-quality (Q) factor (> 10 000) is obtained from well-fabricated CPC C2 microcavity lasers. (c) 2007 American Institute of Physics.
High-index sensitivity of surface mode in photonic crystal hetero-slab-edge microcavity
(2010-05-01)
Lu, Tsan-Wen
;
Hsiao, Yi-Hua
;
Ho, Wei-De
;
Lee, Po-Tsung
;
光電工程學系
We introduce a photonic crystal hetero-slab-edge microcavity design with surface mode, which is beneficial for optical index sensing. The simulated index sensitivity (R(n)) as high as 675 nm per refractive index unit (nm/RIU) variation is obtained with slab thickness of 180 nm. In experiments, single surface mode lasing action from a real device is observed. Based on the surface mode in this microcavity, high experimental R(n) value of 625 nm/RIU is achieved by detecting index variation in a CO(2) chamber with different gas pressures. (C) 2010 Optical Society of America
High-Q Photonic Crystal Hetero-Slab-Edge Microcavity Laser for Index Sensing
(2009)
Hsiao, Yi-Hua
;
Lu, Tsan-Wen
;
Ho, Wei-De
;
Lee, Po-Tsung
;
光電工程學系
We design a photonic crystal hetero-slab-edge microcavity sustaining surface mode with high quality factor similar to 5.4x10(5) and index sensitivity of 591 nm/refractive index unit by mode-gap effect. Lasing actions from real devices are also observed. (C)2009 Optical Society of America
Investigation of whispering gallery mode dependence on cavity geometry of quasiperiodic photonic crystal microcavity lasers
(2006-12-04)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
Lu, Tien-Chang
;
光電工程學系
Dodecagonal (12-fold) quasiperiodic photonic crystal (DQPC) microcavity lasers sustaining whispering gallery mode (WGM) are fabricated. Lasing characteristics of DQPC D2 microcavity lasers are obtained and compared with triangular lattice D2 photonic crystal (PC) lasers, and ultralow threshold is obtained. The strong WGM mode dependence on 12 nearest airholes of DQPC D2 microcavity and its fabrication tolerance is investigated and discussed by randomly varying the lattice of two separate regions. This mode dependence also indicates that one can enhance a WGM in different PC microcavities by modifying the cavity boundary to be circular. (c) 2006 American Institute of Physics.
Laser emissions from one-dimensional photonic crystal rings on silicon-dioxide
(2013-02-04)
Lu, Tsan-Wen
;
Tsai, Wei-Chi
;
Wu, Tze-Yao
;
Lee, Po-Tsung
;
光電工程學系
In this report, we design and utilize one-dimensional photonic crystal ring resonators (1D PhCRRs) to realize InGaAsP/SiO2 hybrid lasers via adhesive bonding technique. Single-mode lasing with low threshold from the dielectric mode is observed. To further design a nanocavity with mode gap effect in 1D PhCRR results in the reduced lasing threshold and increased vertical laser emissions, owing to the reduced dielectric mode volume and the broken rotational symmetry by the nanocavity. Such hybrid lasers based on 1D PhC rings provides good geometric integration ability and new scenario for designing versatile devices in photonic integrated circuits. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790618]
Lasing actions of octagonal quasi-periodic photonic crystal micro-cavities
(2006)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
Lu, Tien-Chang
;
光電工程學系
Lasing actions are obtained from well-fabricated octagonal quasi-periodic photonic crystal (OQPC) micro-cavities. The defect modes in OQPC micro-cavities are investigated and compared with the calculation results. A large single-mode lasing range over 200 nm without mode hopping is observed.
Lasing actions of octagonal quasi-periodic photonic crystal microcavities
(2007-03-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
Lu, Tien-Chang
;
光電工程學系
Lasing actions are obtained from well-fabricated octagonal quasi-periodic photonic crystal (OQPC) microcavities. The defect modes in OQPC microcavities are investigated and compared with the calculation results obtained using the finite-difference time-domain (FDTD) method. A large single-mode lasing wavelength range over 200 nm without mode hopping and a high side-mode suppression ratio (SMSR) of over 30dB are observed, which result from the mode dependence suppression mechanism on the cavity geometry.
Microcavity Laser Emissions Based on Double Hetero-Structure by Locally Modulated Photonic Crystal Waveguide
(2009-10-15)
Chen, Chia-Ho
;
Lu, Tsan-Wen
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
In this paper, we design a microcavity with vertical and in-plane emissions by applying double hetero-structure with mode-gap confinement in photonic crystal waveguide. The hetero-structure is formed by modulating the waveguide width locally by slightly shifting the positions of several nearest air-holes outward. By numerical calculations, we simulate the basic mode profiles and quality (Q) factors of each resonance mode. After optimizing the cavity, high simulated Q factor of 110 000 is obtained. From the well-fabricated devices, we observe the lasing emissions with Q factor of 3200 at wavelength of 1593 nm from both vertical and in-plane directions and address the lasing mode by comparing the measured results with the simulated ones. From the simulated heat transition behaviors by finite-element method, we observe the better heat dissipation provided by the waveguide region in this microcavity. This microcavity laser with locally modulated design could be potentially served as a light source with less influence on the nearby components in photonic integrated circuits.
Modal properties and thermal behaviors of high quality factor quasi-photonic crystal microcavity with different central post sizes
(2008-08-18)
Lu, Tsan-Wen
;
Lee, Po-Tsung
;
Tseng, Chung-Chuan
;
Tsai, Yi-Yu
;
光電工程學系
We investigate the variations of modal properties of 12-fold quasiphotonic crystal microcavities sustaining whispering-gallery (WG) mode with different central post sizes both in simulations and experiments. We realize our design by a series of dry- and wet-etching processes. WG mode lasing actions are obtained with high quality (Q) factor of 8,400 from microcavity with effective post size 420 nm in diameter. Loss and thermal behaviors are analyzed by measured Q factors, thresholds, and rolling-off effects from light-in light-out curves of microcavities with increased post size. By finite-element simulations, we also address the heat sink improvement due to presence of larger central post that is observed in measurements.
Multi-Functional Light Emitter Based on Band-Edge Modes Near Gamma-Point in Honeycomb Photonic Crystal
(2011-06-15)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Sio, Kuan-Un
;
光電工程學系
;
Department of Photonics
In this report, we demonstrate multi-functional light emitter based on band-edge modes near Gamma-point in a two-dimensional honeycomb photonic crystal slab. Different band-edge modes near Gamma-point are identified, including the monopole (Gamma(2)), dipole (Gamma(4,5)) and quadrupole (Gamma(6,7)) modes. The monopole and quadrupole modes lasing are observed with high side-mode suppression-ratio of 35 dB and high index sensitivity of 375 nm per refractive index unit, which shows their potential in optical micro-laser and index sensor applications. Over five-fold photoluminescence enhancement with broad band-width of 100 nm from the dipole mode is also observed at room temperature, which shows the advantage of honeycomb lattice structure for designing high brightness light emitting diodes.
Nanophotonic structures for highly efficient on-chip optical manipulation
(2018-01-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Lin, Pin-Tso
;
Lin, Chia-Yu
;
Tsai, Chia-Yang
In this report, we introduce our proposed nanophotonic structures for highly efficient optical manipulation, including utilizing photonic crystal waveguides, nanocavities, and metallic structures with localized surface plasmon resonances. Owing to their waveguide-accessible configurations and highly concentrated optical modes with large field gradients beyond the diffraction limit, highly efficient optical trapping can be realized in sub-wavelength scale.
Octagonal quasi-photonic crystal single-defect microcavity with whispering gallery mode and condensed device size
(2007-05-01)
Lee, Po-Tsung
;
Lu, Tsan-Wen
;
Tsai, Feng-Mao
;
光電工程學系
;
Department of Photonics
We propose a new single-defect microcavity which supports well-confined whispering gallery mode in octagonal quasi-photonic crystals (OQPC) by shifting the eight nearest air holes around the cavity. Lasing action is observed and compared with the calculated results obtained using the finite-difference time-domain method. We also investigate the threshold dependence on the number of lattice periods of this OQPC microcavity and compare it with triangular lattice photonic crystal (PC) microcavity with similar cavity size. The OQPC microcavity exhibits only a 36% increase of threshold when the number of lattice periods decreases from eight to four, which is more advantageous than the triangular lattice PC microcavity for the shrinkage of device size.
One-dimensional photonic crystal fishbone hybrid nanocavity with nanoposts
(2014-05-12)
Lu, Tsan-Wen
;
Lin, Pin-Tso
;
Lee, Po-Tsung
;
光電工程學系
;
Department of Photonics
We propose and investigate a one-dimensional photonic crystal (PhC) fishbone (FB) hybrid nanocavity lying on silver substrate with a horizontal air slot. With very few PhC periods, the confined transverse-magnetic, TM10 hybrid mode concentrated within the air slot shows high quality factor over effective mode volume ratio larger than 10(5) lambda(-3). Most importantly, this FB hybrid nanocavity allows formation of low-index nanoposts within the air slot without significantly affecting the mode properties. These nanoposts guarantee the structural stabilities under different environmental perturbations. Furthermore, capabilities of our proposed design in serving as optical sensors and tweezers for bio-sized nanoparticles are also investigated. (C) 2014 AIP Publishing LLC.