Article

Quantum cascade lasers with integrated plasmonic antenna-array collimators. Opt Express 16:19447

School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Optics Express (Impact Factor: 3.49). 12/2008; 16(24):19447-61. DOI: 10.1364/OE.16.019447
Source: PubMed

ABSTRACT

We demonstrated in simulations and experiments that by defining a properly designed two-dimensional metallic aperture-grating structure on the facet of quantum cascade lasers, a small beam divergence angle can be achieved in directions both perpendicular and parallel to the laser waveguide layers (denoted as theta perpendicular and theta parallel, respectively). Beam divergence angles as small as theta perpendicular=2.7 degrees and theta parallel=3.7 degrees have been demonstrated. This is a reduction by a factor of approximately 30 and approximately 10, respectively, compared to those of the original lasers emitting at a wavelength of 8.06 microm. The devices preserve good room temperature performance with output power as high as approximately 55% of that of the original unpatterned lasers. We studied in detail the trade-off between beam divergence and power throughput for the fabricated devices. We demonstrated plasmonic collimation for buried heterostructure lasers and ridge lasers; devices with different waveguide structures but with the same plasmonic collimator design showed similar performance. We also studied a device patterned with a "spider's web" pattern, which gives us insight into the distribution of surface plasmons on the laser facet.

Download full-text

Full-text

Available from: Masamichi Yamanishi
  • Source
    • "The direct coupling of a nano-antenna to a PC laser nanocavity offers the possibility to efficiently address the nano-antenna in a compact optical architecture which does not exceed a few cubic microns. Nano-antennas may have also the intriguing ability to finely tune the emission wavelength, spectral linewidth and threshold of a microlaser (as shown here with the BNA) and may also control its emission properties [36]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We show that the near-field coupling between a photonic crystal microlaser and a nano-antenna can enable hybrid photonic systems that are both physically compact (free from bulky optics) and efficient at transferring optical energy into the nano-antenna. Up to 19% of the laser power from a micron-scale photonic crystal laser cavity is experimentally transferred to a bowtie aperture nano-antenna (BNA) whose area is 400-fold smaller than the overall emission area of the microlaser. Instead of a direct deposition of the nano-antenna onto the photonic crystal, it is fabricated at the apex of a fiber tip to be accurately placed in the microlaser near-field. Such light funneling within a hybrid structure provides a path for overcoming the diffraction limit in optical energy transfer to the nanoscale and should thus open promising avenues in the nanoscale enhancement and confinement of light in compact architectures, impacting applications such as biosensing, optical trapping, local heating, spectroscopy, and nanoimaging.
    Full-text · Article · Jun 2014 · Optics Express
  • Source
    • "Nano-antennas have been extensively used in a plethora of applications, ranging from biosensors to near-field optical microscopes and devices, because of their capacity to generate highly intense electric fields in a sub-wavelength scale. Dipole and bowtie antennas, which are constructed by placing a subwavelength dielectric (e.g., air) gap between two metallic regions can confine these fields in nano-scale volumes several orders of magnitude smaller than the wavelength limit defined by the gap's dimensions [1] [2] [3] [4] [5] [6] [7] [8]. They have found applications in excitation of nonlinear effects such as surface enhanced Raman scattering (SERS), visualization and manipulation of nanoparticles and collimation of light. "
    [Show abstract] [Hide abstract]
    ABSTRACT: In this article, a spiral broadband nano-antenna device is studied theoretically and experimentally. This device can produce highly intense electric fields over a wide range of wavelengths, which can be used to excite nonlinear effects such as surface enhanced Raman scattering (SERS) over a wide range of wavelengths or be used to improve the performance of solar cells. SERS enhancement factor higher than 105 can be obtained with this device.
    Full-text · Conference Paper · Aug 2013
  • Source
    • "Nano-antennas have been extensively used in a plethora of applications, ranging from biosensors to near-field optical microscopes and devices, because of their capacity to generate highly intense electric fields in a sub-wavelength scale. Dipole and bowtie antennas, which are constructed by placing a subwavelength dielectric (e.g., air) gap between two metallic regions can confine these fields in nano-scale volumes several orders of magnitude smaller than the wavelength limit defined by the gap's dimensions [1] [2] [3] [4] [5] [6] [7] [8]. They have found applications in excitation of nonlinear effects such as surface enhanced Raman scattering (SERS), visualization and manipulation of nanoparticles and collimation of light. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Fiber optic structures based on multimode interference were investigated to the refractive index (RI) sensing. The proposed device is a singlemode-multimode-singlemode (SMS) structure, where the multimode section is a coreless fiber (MMF). The numerical analyses were carried out by beam propagation and modal expansion methods. Ultra-high sensitivity was obtained: 827 nm/RIU over a RI range of 1.30–1.44 and a maximum sensitivity of 3500 nm/RIU for RI=1.43, considering delta RI = 0.01. The dependence of spectral bandwidth was investigated taking into account the multimode fiber diameter and the coupling efficiency between modes at the input junction singlemode-multimode.
    Full-text · Conference Paper · Oct 2012
Show more