نتایج جستجو برای: acousto
تعداد نتایج: 1196 فیلتر نتایج به سال:
A new all-fiber-optic nonreciprocal device using two acousto-optic frequency shifters is proposed and demonstrated. When the device was operated as an optical isolator, an extinction ratio of 22 dB was obtained. The device's unique modulation capability is also described.
We propose and demonstrate a novel apodization technique for an elliptical-core two-mode fiber acousto-optic filter by twisting the fiber and adjusting the acoustic polarization. The sidelobe suppression in the filter spectrum was improved from -9.7 to -15.5 dB. A theoretical analysis that includes acoustic birefringence explains the experimental results with good agreement.
We have demonstrated high-peak-power generation at 1 kW average power by applying an acousto-optic Q switch to a quasi-cw diode-pumped Nd:YAG master oscillator power amplifier. We achieved a maximum peak power of 2.3 MW by driving the Q switch in burst mode. The average repetition rate was 6 kHz. The corresponding beam quality was M2 = 9.
In the paper, bandwidth parameters of acousto-optical deflectors (AODs) are analyzed from the point of view of acoustical anisotropy. Equations for bandwidth and central frequency of AOD are derived for arbitrary propagation direction of ultrasound in optically uniaxial crystals. The phenomenon of bandwidth shift due to phase mismatch at the central frequency is studied theoretically and verifi...
We propose a tomographic method to reconstruct the optical properties of a highly scattering medium from incoherent acousto-optic measurements. The method is based on the solution to an inverse problem for the diffusion equation and makes use of the principle of interior control of boundary measurements by an external wave field.
This review examines the use of magneto-acoustic methods to measure electrical conductivity. It focuses on two techniques developed in last decades: Magneto-Acoustic Tomography with Magnetic Induction (MAT-MI) and Magneto-Acousto-Electrical (MAET). These developments have potential change way medical doctors image biological tissue.
We demonstrate that anisotropy of Fresnel diffraction in a birefringent medium can be quantitatively characterized by planar tensor. Eigenvectors the tensor correspond to directions minimum and maximum beam divergence. Zero eigenvalues exist for fast eigenmode near optic axis biaxial crystals autocollimated propagation. Applications are demonstrated analysis noncritical phase matching acousto-o...
A finite difference (FD) method is derived for the frequency-domain acoustic and acousto-gravity equations as expressed in cylindrical coordinates. First, it is shown analytically that for an isovelocity atmosphere in which the density decreases exponentially with altitude, the acoustic wave equations (i.e., neglecting gravity) indicate that (1) the pressure varies with the square root of the d...
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