We demonstrate an optomechanical system employing a movable, micron-scale waveguide optically-coupled to a high-Q optical microresonator. We show that milliwatt-level optical powers create micron-scale displacements of the input waveguide. The displacement is caused by a cavity-enhanced optical dipole force (CEODF) on the waveguide, arising from the stored optical field of the resonator. The CEODF is used to demonstrate tunable cavity-waveguide coupling at sub-mW input powers, a form of all-optical tunable filter. The scaling properties of the CEODF are shown to be independent of the intrinsic Q of the optical resonator and to scale inversely with the cavity mode volume.Although light is usually thought of as imponderable, carrying energy but relatively little momentum, light can exert a large force per photon if confined to small structures. Such forces have recently been proposed 1,2 as a means to construct novel optomechanical components such as tunable filters, couplers, and lasers. Other theoretical studies of the nonlinear dynamics of these systems have shown them to be useful for performing optical wavelength conversion and efficient optical-to-mechanical energy conversion 3,4 . In the field of quantum physics, there has also been recent interest in using radiation pressure forces within micro-optomechanical resonators to help cool macroscopic mechanical oscillators to their quantum-mechanical ground state 5,6,7,8 . Here, we demonstrate an optomechanical system employing a movable, micron-scale waveguide optically-coupled to a high-Q optical microresonator. We show that milliwatt-level optical powers create micron-scale displacements of the input waveguide. The displacement is caused by a cavity-enhanced optical dipole force (CEODF) on the waveguide, arising from the stored optical field of the resonator. The CEODF is used to demonstrate tunable cavity-waveguide coupling at sub-mW input powers, a form of all-optical tunable filter. Finally, the scaling properties of the CEODF are shown to be independent of the intrinsic Q of the optical resonator, and to scale inversely with the cavity mode volume, indicating that such forces may become even more effective as devices approach the nanoscale.The ponderomotive effects of light within optical resonators have long been considered in the field of high-precision measurement 9 . The canonical system, shown in Fig. 1a, consists of a Fabry-Perot (FP) resonant cavity formed between a rigid mirror and a movable mirror attached to a spring or hung as a pendulum 10 . A nearly-resonant optical field builds up in amplitude as it bounces back-and-forth between the mirrors and pushes on the movable mirror with each reflection, which detunes the FP cavity. The nonlinear dynamics associated with the displacement of the mirror and the build-up of internal cavity energy result in an "optical spring" effect 11 . Under conditions in which the optical field cannot adiabatically follow the mirror movement, the radiation pressure force can drive or dampen oscillations of the positi...

Abstract:We propose a novel scheme for continuous-wave pumped optical parametric oscillation (OPO) inside silicon micro-resonators. The proposed scheme not only requires a relative low lasing threshold, but also exhibits extremely broad tunability extending from the telecom band to mid infrared.

A tunable nanoscale "zipper" laser cavity, formed from two doubly clamped photonic crystal nanobeams, is demonstrated. Pulsed, room temperature, optically pumped lasing action at = 1.3 m 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 microelectromechanical actuation. Electrostatic tuning over a range of ⌬ = 20 nm for an applied voltage amplitude of 9 V and modulation at a frequency as high as m = 6.7 MHz of the laser wavelength is demonstrated.

Hybridization of surface-plasmon and dielectric waveguide whispering-gallery modes are demonstrated in a semiconductor microdisk laser cavity of subwavelength proportions. A metal layer is deposited on top of the semiconductor microdisk, the radius of which is systematically varied to enable mode hybridization between surface-plasmon and dielectric modes. The anticrossing behavior of the two cavity mode types is experimentally observed via photoluminescence spectroscopy and optically pumped lasing action at a wavelength of ϳ 1.3 m is achieved at room temperature. © 2009 American Institute of Physics. ͓doi:10.1063/1.3266843͔In wavelength-scale lasers, the very small number of optical modes and small volume of gain material allows one to probe the subtle and often interesting properties of lasing action. 1 Semiconductor microdisk lasers, in particular, have been actively studied due to their simple geometry and amenability to planar chip-scale integration with microelectronics. [2][3][4] More recently there has been great interest in using surface-plasmon ͑SP͒ modes at a semiconductormetal interface for guiding as well as high intensity and subwavelength optical confinement. 5 There has been significant work on the incorporation of SP waveguides that also act as electrical contacts in mid-infrared quantum cascade lasers, 6 in increasing SP propagation lengths using SP-dielectric waveguide mode hybridization, 7 as well as in creating ultrasmall laser cavities. 8,9 In miniaturizing semiconductor lasers to the nanoscale one encounters several design challenges that must be addressed, such as thermal management, 10,11 proximity of metal contacts to the optical cavity, surface states, 12 and demanding tolerance levels in fabrication. In this letter, we investigate the purposeful integration of a metal contact into a subwavelength whispering-gallery microdisk laser. We show that whispering-gallery SP and dielectric modes hybridize into low loss modes. We predict and map out this hybridization using finite-element-method ͑FEM͒ simulations, and experimentally measure the properties of fabricated microdisk laser cavities with varying levels of mode hybridization.Simulation of the hybrid laser cavities is performed using fully-three-dimensional FEM simulations with azimuthal symmetry. 13 A 250 nm thick semiconductor disk with index n disk = 3.4 and radius R d = 0.65 m is simulated with a centered metal contact of varying radius ͑R m ͒. A schematic of the microdisk device is shown in Fig. 1͑a͒. Silver with a complex refractive index of n Ag = 0.11− i9.5 at = 1.3 m is chosen for the metal layer due to its low optical loss. 14 For this disk size in the 1300 nm wavelength band there occurs a near degeneracy of the transverse-electric-like ͑TE-like͒ whispering-gallery mode ͑WGM͒ with dominant electric field polarization in the plane of the disk and the transversemagnetic-like ͑TM-like͒ mode with dominant electric field normal to the disk plane. A plot of the wavelength and Q-factor of these two resonances is shown in Fig. 2͑a͒ a...

We report high performance infrared sensors that are based on intersubband transitions in nanoscale self-assembled quantum dots combined with a microcavity resonator made with a high-index-contrast two-dimensional photonic crystal. The addition of the photonic crystal cavity increases the photocurrent, conversion efficiency, and the signal to noise ratio ͑represented by the specific detectivity D * ͒ by more than an order of magnitude. The conversion efficiency of the detector at V b = −2.6 V increased from 7.5% for the control sample to 95% in the PhC detector. In principle, these photonic crystal resonators are technology agnostic and can be directly integrated into the manufacturing of present day infrared sensors using existing lithographic tools in the fabrication facility. © 2006 American Institute of Physics. ͓DOI: 10.1063/1.2194167͔ Infrared sensors in the wavelength range of 3 -25 m are of immense technological importance due to their application in medical diagnostics, fire-fighting equipment, and night vision systems. Quantum dot infrared photodetectors have been identified as an emerging technology for this wavelength regime due to their low dark current leading to a potentially higher operating temperature and normal incidence operation based on a mature GaAs technology. [1][2][3][4][5] Presently, high performance midinfrared detectors are based on mercury cadmium telluride ͑MCT͒. Due to a dramatic change of the band gap as a function of material composition, it is very challenging to reproducibly obtain large area homogeneous materials suitable for large area focal plane arrays ͑FPA͒ based on this material system. In contrast, mature materials growth technologies for III-V semiconductors can provide very accurate control of compositions and homogeneity. Therefore there is interest in developing IR photodetectors using III-V materials. One of the most promising III-V semiconductor long wavelenght infrared ͑LWIR͒ detectors is the quantum well infrared photodetector ͑QWIP͒, 6-9 which employs the intersubband or the subbandto-continuum transitions in quantum wells. One of the drawbacks of n-type QWIPs is that they cannot detect normally incident light due to the restriction of selection rules for the optical transition. In contrast, the intersubband optical transitions in quantum dots ͑QDs͒ do not have that restriction, due to the three-dimensional quantum confinement. Theoretically, quantum dot infrared photodetectors ͑QDIPs͒ and quantum dot-in well ͑DWELL͒ detectors ͑which is a combination of a quantum dot and quantum well detector͒ offer several advantages over QWIPs, including lower dark current ͑hence higher T operation͒, higher responsivity, normal incidence detection, and improved radiation hardness. 10,11 QDIPs with low dark current densities and high operating temperature have been reported. 2,3 Asymmetrically designed DWELL detectors have also been shown to have a biasdependent spectral response that is suitable for multispectral imagery. 12 Recently, a two color 320ϫ 256 FPA, based on a volt...