The objective of this program is to demonstrate current injection, continues-wave lasing action at room temperature from sub-wavelength-scale disk resonators by developing high-quality modes in the proximity of low-loss conductive media and provide CMOS-compatible buildings blocks based on nanocavities that require current injection and electric field application. The developed nano-resonators will also be used as external nano-modulators.
Intellectual merit is in developing practical, planar nanolasers that is smaller than one wavelength of lasing mode in vacuum. A challenge to build current injection nanolasers arises from the difficulty of suppressing absorption of light by electrode metal. The PI?s approach to build sub-wavelength-scale current-injection nanolasers is to use simple, high-Q disk nanocavity designs with transparent conductive oxide (TCO) electrodes such as indium tin oxide (ITO). The PI?s designs with TCO media have advantages, including large thermal conductance, small electric resistance, and large quantum efficiency via the direct current injection to small lasing modes.
The broader impacts are in inducing the development of on-chip photonics systems, such as optical interconnect chips, lab-on-chip, quantum information chips, imaging devices, and data storage chips, via the development of breakthrough technology in nanolasers. The electrically-controlled light localization technology would break the boundary set by present light localization technology and open up possibilities of creating new light localization devices and enhance the performance and functionality of optical devices. The program will provide excellent outreach opportunities by creating online, hands-on, free scientific curriculums.
We have continued enhance our fast algorithms based on spectral elements for modeling linear and nonlinear optics, and have applied these algorithms to simulate and design advanced nanophotonic devices: (a) Huge enhancement of second harmonic generation by photonic crystal slabs and Bradd reflector. By engineering a 3-D air-bridge photonic crystal slab with a multiple layer dielectric structure, a 63-layer structure with a total thickness less than 8 microns is designed to achieve large enhancement of the second harmonic generation effect by almost 10 orders of magnitude, with an output second harmonic field power rate of more than 0.1% under a typical laser incident field of 0.5 MV/m. One potential application of this device is that it can produce highly monochromatic light. This result is 6 orders of magnitude better than what we achieved in 2013, and the paper reporting this result has been submitted for publication. (b) Extreme ultraviolet (EUV) lithography is an emerging technology for high density semiconductor patterning. The multilayer distortion caused by the mask defects is regarded as one of the critical challenges of EUV lithography. To simulate the influence of the defected nano-scale structures with high accuracy and efficiency, we have developed a boundary integral spectral element method (BI-SEM) that combines the SEM with a set of surface integral equations. The SEM is used to solve the interior computational domain, while the open boundaries are truncated by the surface integral equations. Both 2-dimensional and 3-dimensional EUV cases are simulated. Through comparing the performance of this method with the conventional finite element method, it is shown that the proposed BI-SEM can greatly decrease both the memory cost and computation time. For typical 2-D problems, we show that the BI-SEM is 11 and 1.25 times more efficient than the finite element method (FEM) in terms of memory and CPU time, respectively, while for 3-D problems, these factors are over 14 and 2, respectively, for smaller problems; realistic 3-D problems that cannot be solved by the conventional FEM can be accurately simulated by the BI-SEM. A paper has been published in JOSA B. (c) We have developed a new multiscale discontinuous Galerkin time domain (DGTD) method to simulate large and complex electromagnetic problems. A paper has been published in the Journal of Computational Physics. Journal papers and conference papers published in Year 3: M. Luo, Q. H. Liu, "Extraordinary enhancement of second harmonic generation in a periodically patterned distributed Bragg reflector," submitted for publication. J. Chen, L. Tobon, and Q. H. Liu, "Locally implicit discontinuous Galerkin finite element method for transient analysis of 3D layered structures with electrically small details," Microwave Opt. Technol. Lett., vol. 55, no. 8, 1912-1916, DOI: 10.1002/mop.27673, Aug. 2013. J. Niu, M. Luo, Y. Fang, Q. H. Liu, "Boundary integral spectral element method analyses of extreme ultraviolet multilayer defects," J. Opt. Soc. Am. A, vol. 31, no. 10, pp. 2203-2209, Oct. 2014. L. Tobon, Q. Ren, and Q. H. Liu, "Spectral-Prism Element for Multi-Scale Layered Package-Chip Co-Simulations Using the Discontinuous Galerkin Time-Domain Method," Electromagnetics, vol. 34, no. 3-4, Special Issue, pp. 270-285, April 2014. J. Niu, M. Luo, J. Zhu, Q. H. Liu, "Light Absorption Manipulation of Graphene: Simulation by Boundary Integral Spectral Element Method" Optics Express, Vol. 23, No. 4, Feb 2015. J. Niu, M. Luo, Q. H. Liu, "Full-Wave Third Harmonic Generation Analyses of Graphene-Based Optoelectronic Devices," to be submitted. J. Niu, M. Luo, and Q. H. Liu, "Boundary Integral Spectral Element Method for Extreme Ultraviolet Multilayer Defects Analyses," IEEE APS/URSI Meeting, Memphis, TN, July 2014. Q. H. Liu, Q. Ren, L. Tobon, and Q. Sun, "New Discontinuous Galerkin SETD and FETD Methods for Multiscale Electormagnetics," FEM2014, Chengdu, May 2014. Invited Talk. Q. Ren, L. Tobon, Q. Sun, and Qing Huo Liu, "The Hybrid SETD-FETD Method with Field Variables E and B," IEEE APS/URSI Meeting, Memphis, TN, July 2014. 10. J. Niu, M. Luo, J. Zhu, Q. H. Liu, "Enhanced Surface Plasmonic Optical Absorption Engineering of Graphene: Simulation by Boundary-Integral Spectral Element Method," 2015 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, Vancouver, Canada, July 2015. 11. J. Niu, M. Luo, Q. H. Liu, "Full-Wave Third Harmonic Generation Analyses of Graphene-Based Optoelectronic Devices," 2015 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, Vancouver, Canada, July 2015.