High-frequency acousto-optic effects in Bragg reflectors

Farmer, David John; Akimov, A. V.; Gippius, N. A.; Bailey, James; Sharp, James S.; Kent, A. J.

doi:10.1364/oe.22.015218

Cited by 4 publications

(4 citation statements)

References 43 publications

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“…Compared to piezoelectric transducer, a laser beam can be a good sensor to receive ultrasound with no interference from the sound field, which is based on the acousto-optic effect. Acousto-optics has been widely used to make tunable optical filters, modulators, and Q-switches [26][27][28][29][30]. Research focused on quantitative analyses for ultrasound that uses acousto-optic diffraction began with Raman and Nath [31] in 1936.…”

Section: Introductionmentioning

confidence: 99%

A High-Resolution Ultrasonic Ranging System Using Laser Sensing and a Cross-Correlation Method

et al. 2019

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Ultrasound has been proven to be a valid tool for ranging, especially in water. In this paper, we design a high-resolution ultrasonic ranging system that uses a thin laser beam as an ultrasonic sensor. The laser sensing provides a noncontact method for ultrasound detection based on acousto-optic diffraction. Unlike conventional methods, the ultrasound transmitted from the transducer is recorded as the reference signal when it first passes through the laser. It can be used to improve the accuracy and resolution of the time-of-flight (TOF) by a cross-correlation method. Transducers with a central frequency of 1 MHz and diameters of 20 mm and 28 mm are used in the experiment. Five targets and a test piece are used to evaluate the ranging performance. The sound velocity is measured by the sound velocity profiler (SVP). The repeatability error of TOF is less than 4 ns, and the theoretical resolution of TOF is 0.4 ns. The results show a measurement resolution within one-tenth of the wavelength of ultrasound and an accuracy better than 0.3 mm for targets at a distance up to 0.8 m. The proposed system has potential applications in underwater ranging and thickness detection.

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Section: Introductionmentioning

confidence: 99%

A High-Resolution Ultrasonic Ranging System Using Laser Sensing and a Cross-Correlation Method

et al. 2019

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“…The advantage of optomechanical systems is their relative compactness, enabling manipulation of spectrum of classical and quantum light on the nanoscale [5,6]. Specifically, mechanical motion or deformation leads to a dynamical modification of optical properties such as refractive index [7], resonance frequency [8] and optical gain [9], allowing one to control light intensity and frequency [10,11], as well as propagation direction [12]. The simplest example of motion-induced frequency conversion is given by the Doppler effect.…”

Section: Introductionmentioning

confidence: 99%

Doppler-Raman crossover in resonant scattering by a moving layer

2020

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We consider theoretically light scattering by a resonant layer that periodically moves in real space. At small frequencies of motion the scattered light spectrum reveals the frequency shift that is governed by the Doppler effect. At higher motion frequencies, the scattered light spectra acquire sidebands stemming from the Raman effect. We investigate the crossover between these two regimes and propose a realistic quantum well structure for its observation.

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“…Whilst very useful and valid chemical information can be obtained from thin films of less than ~1 μm in depth, there have only been a few investigations of thicker films and therefore there is a lack of understanding of the factors that may limit the depth to which useful depth profiles may be performed. Such understanding is vital for the application of this method to well‐defined polymer multilayer materials that are used for optical filters and reflectors, polymer electronic devices, solar cells, and drug delivery.…”

Section: Introductionmentioning

confidence: 99%

Sample rotation improves gas cluster sputter depth profiling of polymers

Smith

Counsell

Bailey

et al. 2017

Surf Interface Anal

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X-ray photoelectron spectroscopy (XPS) was used in conjunction with gas cluster ion source etching to analyze polystyrene and polyvinylpyrrolidone multilayer samples, total thickness~15 μm, to establish optimal conditions for depth profiles over many μm in depth. Using standard conditions, these samples demonstrate a reduction in depth resolution and sputtering yield, which is shown to be partly due to X-ray-induced damage and partly due to roughening of the sputtered surface. By limiting the X-ray exposure, it was possible to retain depth resolution to a depth of approximately 5 μm; to obtain useful depth profiles beyond this depth, it was necessary to use sample rotation. The use of optimized conditions allowed the chemical integrity of the polymer layers to remain intact during the etching process with relatively sharp interfaces over the full depth of the films. Both the elemental intensities in XPS and the line shape of the C 1s peak could be used to determine the differences in chemical structure of the films in the depth profile.Detailed analysis suggests that a "stepwise" rotation scheme can maintain depth resolution better than continuous rotation during sputtering.

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High-frequency acousto-optic effects in Bragg reflectors

Cited by 4 publications

References 43 publications

A High-Resolution Ultrasonic Ranging System Using Laser Sensing and a Cross-Correlation Method

A High-Resolution Ultrasonic Ranging System Using Laser Sensing and a Cross-Correlation Method

Doppler-Raman crossover in resonant scattering by a moving layer

Sample rotation improves gas cluster sputter depth profiling of polymers

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