There has been considerable interest in metallic nanolasers recently and some forms of these devices constructed from semiconductor pillars can be considered as surface-emitting lasers. We compare two different realized versions of these nanopillar devices, one with a trapped cutoff mode in the pillar, another with a mode that propagates along the pillar. For the cutoff mode devices we introduce a method to improve the output beam characteristics and look at some of the challenges in improving such devices. 1. Introduction Since the invention of the first laser by Maiman [1] in 1960, different lines of development have yielded lasers the size of buildings, or as small as a few tens of nanometers. Perhaps the greatest impact on society has been had with making lasers smaller. In particular, the invention of the semiconductor laser [2] has allowed small, electrically driven lower power coherent light sources. One of the later developments in the miniaturization of the laser has been the vertical cavity surface-emitting laser or VCSEL [3]. The VCSEL was the first laser with dimensions which approached the wavelength scale. The VCSEL has found many applications due in part to the following characteristics: electrical pumping, room temperature operation, reasonable efficiency, small threshold current, useful output beam characteristics, and ease of test and manufacture owing to the surface normal output. In the last few years the use of metals to form nanoscale resonators for lasers has been explored. Metals have allowed a dramatic decrease in both the size of the optical mode and also the overall size of the laser. Some of the initial devices are given roughly in chronological order in [4–12]. Some of these devices involve plasmonic waveguide modes [5, 7]. Others show lasing with a nanoparticle as a resonator [6]. Others involve the encapsulation of small pillars of semiconductor material [4, 10, 12]. In these particular devices, light escapes from one end of the pillar. Such devices can be considered as surface-emitting lasers. In this article we will look at a number of aspects of such devices. 2. Pillar-Based Metal Nanolasers Two main types of surface-emitting devices have been proposed thus far. The first sort of device involves encapsulating a heterostructure pillar [4, 10], which has a higher index in the center of the pillar, Figure 1(a). In the devices we have made, the lower index material consists of InP and the higher index InGaAs. The mode of interest which resonates in such a pillar has a frequency close to the cutoff frequency of the circular
References
[1]
T. H. Maiman, “Stimulated optical radiation in Ruby,” Nature, vol. 187, no. 4736, pp. 493–494, 1960.
[2]
R. N. Hall, G. E. Fenner, J. D. Kingsley, T. J. Soltys, and R. O. Carlson, “Coherent light emission from GaAs junctions,” Physical Review Letters, vol. 9, no. 9, pp. 366–368, 1962.
[3]
K. Iga, “Surface-emitting laser—its birth and generation of new optoelectronics field,” IEEE Journal on Selected Topics in Quantum Electronics, vol. 6, no. 6, pp. 1201–1215, 2000.
[4]
M. T. Hill, Y. S. Oei, B. Smalbrugge et al., “Lasing in metallic-coated nanocavities,” Nature Photonics, vol. 1, no. 10, pp. 589–594, 2007.
[5]
M. T. Hill, M. Marell, E. S. P. Leong et al., “Lasing in metal-insulator-metal sub-wavelength plasmonic waveguides,” Optics Express, vol. 17, no. 13, pp. 11107–11112, 2009.
[6]
M. A. Noginov, G. Zhu, A. M. Belgrave et al., “Demonstration of a spaser-based nanolaser,” Nature, vol. 460, no. 7259, pp. 1110–1112, 2009.
[7]
R. F. Oulton, V. J. Sorger, T. Zentgraf et al., “Plasmon lasers at deep subwavelength scale,” Nature, vol. 461, no. 7264, pp. 629–632, 2009.
[8]
R. Perahia, T. P. M. Alegre, A. H. Safavi-Naeini, and O. Painter, “Surface-plasmon mode hybridization in subwavelength microdisk lasers,” Applied Physics Letters, vol. 95, no. 20, Article ID 201114, 2009.
[9]
K. Yu, A. Lakhani, and M. C. Wu, “Subwavelength metal-optic semiconductor nanopatch lasers,” Optics Express, vol. 18, no. 9, pp. 8790–8799, 2010.
[10]
M. P. Nezhad, A. Simic, O. Bondarenko et al., “Room-temperature subwavelength metallo-dielectric lasers,” Nature Photonics, vol. 4, no. 6, pp. 395–399, 2010.
[11]
S. H. Kwon, J. H. Kang, C. Seassal et al., “Subwavelength plasmonic lasing from a semiconductor nanodisk with silver nanopan cavity,” Nano Letters, vol. 10, no. 9, pp. 3679–3683, 2010.
[12]
C. Y. Lu, S. W. Chang, S. L. Chuang, T. D. Germann, and D. Bimberg, “Metal-cavity surface-emitting microlaser at room temperature,” Applied Physics Letters, vol. 96, no. 25, Article ID 251101, 2010.
[13]
A. Matsudaira, C.-Y. Lu, S. L. Chuang, and L. Zhang, “Demonstartion of metallic nano-cavity light emitters with electrical injection,” in Conference on Lasers and Electro-Optics (CLEO '11), 2011.
[14]
A. V. Maslov and C. Z. Ning, “Size reduction of a semiconductor nanowire laser by using metal coating,” in Physics and Simulation of Optoelectronic Devices XV, Proceedings of SPIE, January 2007.
[15]
K. Iga, F. Koyama, and S. Kinoshita, “Surface emitting semiconductor lasers,” IEEE Journal of Quantum Electronics, vol. 24, no. 9, pp. 1845–1855, 1988.
[16]
C. E. Hofmann, F. J. García De Abajo, and H. A. Atwater, “Enhancing the radiative rate in III-V semiconductor plasmonic core-shell nanowire resonators,” Nano Letters, vol. 11, no. 2, pp. 372–376, 2011.
[17]
E. K. Lau, A. Lakhani, R. S. Tucker, and M. C. Wu, “Enhanced modulation bandwidth of nanocavity light emitting devices,” Optics Express, vol. 17, no. 10, pp. 7790–7799, 2009.
[18]
S. W. Chang, T. R. Lin, and S. L. Chuang, “Theory of plasmonic Fabry-Perot nanolasers,” Optics Express, vol. 18, no. 14, pp. 14913–14925, 2010.
[19]
P. B. Johnson and R. W. Christy, “Optical constants of the noble metals,” Physical Review B, vol. 6, no. 12, pp. 4370–4379, 1972.
[20]
A. Mizrahi, V. Lomakin, B. A. Slutsky, M. P. Nezhad, L. Feng, and Y. Fainman, “Low threshold gain metal coated laser nanoresonators,” Optics Letters, vol. 33, no. 11, pp. 1261–1263, 2008.
[21]
J. Huang, S. H. Kim, and A. Scherer, “Design of a surface-emitting, subwavelength metal-clad disk laser in the visible spectrum,” Optics Express, vol. 18, no. 19, pp. 19581–19591, 2010.
[22]
H. J. Lezec, A. Degiron, E. Devaux et al., “Beaming light from a subwavelength aperture,” Science, vol. 297, no. 5582, pp. 820–822, 2002.
[23]
S. Silver, Microwave Antenna Theory and Design, McGraw-Hill, New York, NY, USA, 1949.
[24]
B. T. Lee, T. R. Hayes, P. M. Thomas, R. Pawelek, and P. F. Sciortino, “SiO2 mask erosion and sidewall composition during CH4/H2 reactive ion etching of InGaAsP/InP,” Applied Physics Letters, vol. 63, no. 23, pp. 3170–3172, 1993.
[25]
H. Wang, M. Sun, K. Ding, M. T. Hill, and C.-Z. Ning, “A top-down approach to fabrication of high quality vertical heterostructure nanowire arrays,” Nano Letters, vol. 11, no. 4, pp. 1646–1650, 2011.
[26]
L. G. Shantharama, H. Schumacher, H. P. Leblanc, R. Esagui, R. Bhat, and M. Koza, “Evaluation of single ohmic metallisations for contacting both p- and n-type GaInAs,” Electronics Letters, vol. 26, no. 15, pp. 1127–1129, 1990.
[27]
M. Kuttge, E. J. R. Vesseur, J. Verhoeven, H. J. Lezec, H. A. Atwater, and A. Polman, “Loss mechanisms of surface plasmon polaritons on gold probed by cathodoluminescence imaging spectroscopy,” Applied Physics Letters, vol. 93, no. 11, Article ID 113110, 2008.
[28]
J. -S. Huang, V. Callegari, P. Geisler et al., “Atomically flat single-crystalline gold nanostructures for plasmonic nanocircuitry,” Nature Communications, vol. 1, no. 9, article 150, 2010.
