Press-induced long-period fiber gratings exhibiting strong core-to-cladding mode coupling were formed in photonic crystal fiber. Only one resonance peak was observed over a 600 nm spectral range and the resonant wavelength was tuned over the whole range by tilting a groove plate before pressing the fiber. The resonant wavelength decreased with increasing periodicity of the grating, which was op...

A piezoelectric tube is shown to have linear, but non-minimum phase dynamics. The main impediment to the actuation of this piezoelectric tube is the presence of a low-frequency resonant mode which causes mechanical vibrations. A physical-model-based control method is extended to non-minimum phase systems in general and successfully applied to damp the resonant mode; leading to a vibration-free ...

A piezoelectric tube of the type typically used for actuation in Scanning Tunneling Microscopes (STMs) and Atomic Force Microscopes (AFMs) is considered. Actuation of this piezoelectric tube is hampered by the presence of a lightly damped low frequency resonant mode. This resonant mode is first identified and then damped using a Positive Velocity and Position Feedback (PVPF) controller, a contr...

We report 56% efficient external cavity resonant second harmonic generation of a diode-laser pumped, CW single-axial-mode Nd :YAG laser. A theory of external doubling with a resonant fundamental is presented and compared to experimental results for three monolithic cavities of nonlinear MgO : LiNb03. The best conversion efficiency was obtained with a 12.5 mm long monolithic ring cavity doubler,...

We present a co-axial dual-core resonant leaky optical fibre design, in which the outer core is made highly leaky. A suitable choice of parameters can enable us to resonantly couple power from the inner core to the outer core. In a large-core fibre, such a resonant coupling can considerably increase the differential leakage loss between the fundamental and the higher order modes and can result ...

We describe a new atom interferometric gravitational wave detector design that can operate in a resonant mode for increased sensitivity. By oscillating the positions of the atomic wavepackets, this resonant detection mode allows for coherently enhanced, narrow-band sensitivity at target frequencies. The proposed detector is flexible and can be rapidly switched between broadband and narrow-band ...

We report the observation of strong coupling of a macroscopic ensemble of ∼1016 Fe8 molecular nanomagnets to the resonant mode of a microwave cavity. We use millimeter-wave spectroscopy to measure the splitting of the system's resonant frequency induced by the coupling between the spins and the cavity mode. The magnitude of this splitting is found to scale with √N, where N is the number of coll...

We present a novel, hand-held microscope probe for acquiring confocal images of biological tissue. This probe generates images by scanning a fiber-lens combination with a miniature electromagnetic actuator, which allows it to be operated in resonant and nonresonant scanning modes. In the resonant scanning mode, a circular field of view with a diameter of 190 μm and an angular frequency of 127 H...

Electronic speckle pattern interferometry (ESPI) was used for tuning and visualization of natural frequencies of a square laminate plate with rounded corners and chamfers. The plate was excited to resonant vibration by a sinusoidal acoustical source, which provided a continuous range of audio frequencies. Numerical calculations of resonant frequencies and mode shapes based on a finite element p...

It is shown that pulsar radio emission can be generated effectively through a streaming motion in the polar-cap regions of a pulsar magnetosphere causing non-resonant growth of waves that can escape directly. As in other beam models, a relatively low-energy high-density beam is required. The instability generates quasitransverse waves in a beam mode at frequencies that can be well below the res...