11 research outputs found
Electrostatically tunable optomechanical "zipper" cavity laser
A tunable nanoscale "zipper" laser cavity, formed from two doubly clamped
photonic crystal nanobeams, is demonstrated. Pulsed, room temperature,
optically pumped lasing action at a wavelength of 1.3 micron is observed for
cavities formed in a thin membrane containing InAsP/GaInAsP quantum-wells.
Metal electrodes are deposited on the ends of the nanobeams to allow for
micro-electro-mechanical actuation. Electrostatic tuning and modulation of the
laser wavelength is demonstrated at a rate of 0.25nm/V^2 and a frequency as
high as 6.7MHz, respectively.Comment: 4 pages, 4 figure
Proof-of-principle of surface detection with air-guided quantum cascade lasers
We report a proof-of-principle of surface detection with air-guided quantum cascade lasers. Laser ridges were designed to exhibit an evanescent electromagnetic field on their top surface that can interact with material or liquids deposited on the device. We employ photoresist and common solvents to provide a demonstration of the sensor setup. We observed spectral as well as threshold currents changes as a function of the deposited material absorption curve. A simple model, supplemented by 2D numerical finite element method simulations, allows one to explain and correctly predict the experimental results
Quantum dot photonic crystal detectors
In this paper we report the use of a photonic crystal resonant cavity to increase the quantum efficiency, detectivity (D*) and the background limited infrared photodetector (BLIP) temperature of a quantum dot detector. The photonic crystal is incorporated in InAs/InGaAs/GaAs dots-in-well (DWELL) detector using Electron beam lithography. From calibrated blackbody measurements, the conversion efficiency of the detector with the photonic crystal (DWELL-PC) is found to be 58.5% at -2.5 V while the control DWELL detectors have quantum efficiency of 7.6% at the same bias. We observed no significant reduction in the dark current of the photonic crystal devices compared to the normal structure. The generation-recombination limited D* at 77K with a 300K F1.7 background, is estimated to be 6 x 10^(10) cm Hz^(1/2)/W at -3V bias for the DWELL-PC which is a factor of 20 higher than that of the control sample. We also observed a 20% increase in the BLIP temperature for the DWELL-PCs
Towards on-chip tunable nanolasers based on optomechanical zipper cavities
Work towards semiconductor nanolasers at λ = 1.3 μm in optomechanically coupled one
dimensional photonic-crystal cavities is presented. Optical mode spectroscopy and on-chip tuning capability
based on capacitive actuation is developed. Experimental and theoretical results are presented
Optomechanical zipper cavity lasers: theoretical analysis of tuning range and stability
The design of highly wavelength tunable semiconductor laser structures is
presented. The system is based on a one dimensional photonic crystal cavity
consisting of two patterned, doubly-clamped nanobeams, otherwise known as a
"zipper" cavity. Zipper cavities are highly dispersive with respect to the gap
between nanobeams in which extremely strong radiation pressure forces exist.
Schemes for controlling the zipper cavity wavelength both optically and
electrically are presented. Tuning ranges as high as 75nm are achieved for a
nominal design wavelength of 1.3micron. Sensitivity of the mechanically
compliant laser structure to thermal noise is considered, and it is found that
dynamic back-action of radiation pressure in the form of an optical or
electrical spring can be used to stabilize the laser frequency. Fabrication of
zipper cavity laser structures in GaAs material with embedded self-assembled
InAs quantum dots is presented, along with measurements of photoluminescence
spectroscopy of the zipper cavity modes.Comment: 20 pages, 8 figure
Quantum Cascade Microdisk Lasers for Mid Infrared Intra-Cavity Sensing
The design, fabrication, and testing of surface sensitive quantum cascade microdisk lasers in the mid-infrared for intra-cavity spectroscopy and integration with microfluidic delivery is presented
Quantum dot photonic crystal detectors
In this paper we report the use of a photonic crystal resonant cavity to increase the quantum efficiency, detectivity (D*) and the background limited infrared photodetector (BLIP) temperature of a quantum dot detector. The photonic crystal is incorporated in InAs/InGaAs/GaAs dots-in-well (DWELL) detector using Electron beam lithography. From calibrated blackbody measurements, the conversion efficiency of the detector with the photonic crystal (DWELL-PC) is found to be 58.5% at -2.5 V while the control DWELL detectors have quantum efficiency of 7.6% at the same bias. We observed no significant reduction in the dark current of the photonic crystal devices compared to the normal structure. The generation-recombination limited D* at 77K with a 300K F1.7 background, is estimated to be 6 x 10^(10) cm Hz^(1/2)/W at -3V bias for the DWELL-PC which is a factor of 20 higher than that of the control sample. We also observed a 20% increase in the BLIP temperature for the DWELL-PCs
Actuation of Micro-Optomechanical Systems Via Cavity-Enhanced Optical Dipole Forces
We demonstrate a new type of optomechanical system employing a movable,
micron-scale waveguide evanescently-coupled to a high-Q optical microresonator.
Micron-scale displacements of the waveguide are observed for
milliwatt(mW)-level optical input powers. Measurement of the spatial variation
of the force on the waveguide indicates that it arises from a cavity-enhanced
optical dipole force due to the stored optical field of the resonator. This
force is used to realize an all-optical tunable filter operating with sub-mW
control power. A theoretical model of the system shows the maximum achievable
force to be independent of the intrinsic Q of the optical resonator and to
scale inversely with the cavity mode volume, suggesting that such forces may
become even more effective as devices approach the nanoscale.Comment: 4 pages, 5 figures. High resolution version available at
(http://copilot.caltech.edu/publications/CEODF_hires.pdf). For associated
movie, see (http://copilot.caltech.edu/research/optical_forces/index.htm