We report amplification of sub-10-100 ns pulses with repetition rates from 1 to 20 kHz in a rod-type thulium-doped photonic crystal fiber with 80 μm core diameter. The rod is pumped with a 793 nm laser diode and produces the highest peak power at 1 kHz repetition rate with 6.5 ns pulse duration and more than 7 W average output power. This result exemplifies the potential of this fiber design to...

We investigate the generation of the screeching sound commonly heard during tape peeling using synchronised high-speed video and audio acquisition. We determine the peak frequencies in the audio spectrum and, in addition to a peak frequency at the upper end of the audible range (around 20 kHz), we find an unexpected strong sound with a high-frequency far above the audible range, typically aroun...

The ultrasonic conditions of different sonochemical reactors can be tuned to obtain Pt-nanoparticles similar sizes. At low frequencies (20 kHz) Ti/V/Al-contaminants were produced due the probe erosion leading improved kinetics.

Interdigitated finger (comb) structures are demonstrated to be effective for exciting electrostatically the resonance of polysilicon microstructures parallel to the plane of the substrate. Linear plates suspended by a folded-cantilever truss and torsional plates suspended by spiral and serpentine springs are fabricated from a 2/~m-thick phosphorus-doped low-pressure chemical-vapordeposited (LPC...

In this paper, an algorithm for coding 20 Hz 15 kHz speech signals at 64 kbit/s with a very low delay (frame of 0.16 ms) is presented. To achieve a quality near to transparency, we propose adapting the Low-Delay CELP coder [1] to the 15 kHz bandwidth and suggest a new noise shaping method based on a psychoacoustic model. In this way we take advantage of linear predictive coding and masking prop...

ABSTRACT—A low-voltage and low-power bandpass ∆Σ modulator is described. In this design, two novel ideas are incorporated: unity-gain-reset and integrating-two-path techniques. A test chip, realized in a 0.35-μm CMOS process and clocked at both 20 and 40MHz, provided a dynamic range DR=45dB and a signal-to-noise+distortion-ratio SNDR=36dB for a 100-kHz signal bandwidth at 5MHz center frequency,...

We demonstrate in vivo optical coherence tomography using a Fourier-domain optical delay line constructed with a commercially available polygonal scanner. The 20-faceted polygonal mirror array, capable of scanning at rates up to 15 kHz, is implemented at 4 kHz to acquire 500 x 500 pixel images at 8 frames/s with a signal-to-noise ratio of 80 dB. Features of this delay line include scalability t...

Although the spatial focusing property of the conventional time reversal approach facilitates multiuser communications, there always is residual crosstalk between users. A recent paper [Kim and Shin, J. Acoust. Soc. Am. 115, 600-606 (2004)] proposed an adaptive active time reversal approach for simultaneous multiple focusing with minimal interference. This letter applies the adaptive approach t...

We demonstrate photothermal optical coherence tomography (OCT) imaging in highly scattering human breast tissue ex vivo. A 120 kHz axial scan rate, swept-source phase-sensitive OCT system at 1300 nm was used to detect phase changes induced by 830 nm photothermal excitation of gold nanoshells. Localized phase modulation was observed 300-600 microm deep in scattering tissue using an excitation po...

This paper deals with the design of novel sub-1-V bandgap reference circuit using only MOS transistors in 0.18 μm CMOS technology, for a supply voltage of 1.8V. The circuit produces a voltage reference of 466.5 mV at 27C with a temperature coefficient of 28.4 ppm/C in the range of -20 to +120C. The power supply rejection of circuit is -30 dB at 8 KHz and this rejection further increase to -50 d...