Planar ortho-mode transducers (OMTs) are a commonly used method of coupling optical signals between waveguides and on-chip circuitry detectors. While the ideal OMT-waveguide requires minimal disturbance to waveguide, when for mm-wave applications waveguide is typically constructed from two sections allow OMT probes be inserted into waveguide. This break in source signal leakage can lead loss pe...

A dual-transducer system was used to test concepts for on-line guidance and lesion monitoring during ultrasound therapy. The system used a spherical-cap therapy transducer (4 MHz; 40-mm dia.; 90-mm focus) with a central, collinear transducer (7.5 MHz; 10-mm dia.) for A-mode examination. A digital system provided 3 operational modes, tested in in-vitro liver. Mode 1 senses in-situ therapy-beam h...

We report on the synergy of an integrated ultrasound (US) and photoacoustic (PA) probe system for intravascular imaging. The combined dual-modality probe is based on a 39 MHz ring-shaped US transducer which detects both US echoes and laser-generated PA signals. By combining optical fiber, US transducer, and micromirror, we can obtain intravascular cross-sectional B-scan images by internal illum...

A high fidelity interferometric transducer is designed based on platinum-coated nanoporous alumina films. The ultrathin metal coating significantly improves fidelity of the interferometric fringe patterns in aqueous solution and increases the signal-to-noise ratio. The performance of this transducer is tested with respect to refractive index unit (RIU) sensitivity measured as a change in effect...

We present the photoacoustic imaging velocimetry (PAIV) method for flow-field measurement based on a linear transducer array. The PAIV method is realized by using a Q-switched pulsed laser, a linear transducer array, a parallel data-acquisition equipment and dynamic focusing reconstruction. Tracers used to track liquid flow field were real-timely detected, two-dimensional (2-D) flow visualizati...

A flexible and low-cost optical fiber transducer based on light attenuation by microbending was designed for the measurement of angular displacements. The transducer was tested for predetermined rotations, presenting a higher sensitivity for angles >10° by spacing the periodicity of the deformers by 2 mm. In addition, the performance on the measurement of angles <10° was also enhanced by the sp...

An optical fiber with nano-electromechanical functionality is presented. The fiber exhibits a suspended dual-core structure that allows for control of the optical properties via nanometer-range mechanical movements. We investigate electrostatic actuation achieved by applying a voltage to specially designed electrodes integrated in the cladding. Numerical and analytical calculations are preforme...

Dynamic response of a dual-frequency liquid crystal (DFLC) based near infrared phase modulator is investigated through numerical simulations and experiments. The relationships between the optical response times and various voltage driving conditions are studied. An optical phase retarder operating at 1.55 lm wavelength is demonstrated by using our homemade high figure-of-merit DFLC mixture. To ...

We report an infrared (IR) optical switch using a position-shifting glycerol droplet. The droplet is surrounded by density-matched oil. In the voltage-on state, the droplet shifts in one direction. Upon removing the voltage, the droplet returns to its original position with the aid of interfacial tensions. Due to the strong absorption of glycerol at 1.55 lm, our IR optical switch shows 95:1 con...

Abstract. For the experimental measurements of pyroelectric detectors voltage responsivity, sinusoidal modulated optical radiation should be used. In practice, optical choppers are commonly used in experimental set-ups to modulate optical source and as a result optical radiation may have a square or trapezoidal waveform. In the paper, the frequency dependence of voltage responsivity of pyroelec...