%0 Journal Article
%T Surface-Emitting Metal Nanocavity Lasers
%A Martin T. Hill
%A Milan J. H. Marell
%J Advances in Optical Technologies
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/314952
%X 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¨C12]. 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
%U http://www.hindawi.com/journals/aot/2011/314952/