RESUMO
We present a new instrument, based on a low-frame-rate (8 Hz) CCD camera used in a heterodyne optical-mixing configuration, that can create wide-field laser Doppler maps. As an illustration, we show results obtained in a mouse brain, in vivo, showing the Doppler signature of blood flow. The instrument is based on a frequency-shifting digital holography scheme.
Assuntos
Crânio/irrigação sanguínea , Animais , Fluxometria por Laser-Doppler , Lasers , Camundongos , Camundongos Endogâmicos C57BL , Fluxo Sanguíneo Regional , Espalhamento de RadiaçãoRESUMO
A new technique is presented for measuring the spectral broadening of light that has been multiply scattered from scatterers in motion. In our method the scattered light is detected by a heterodyne receiver that uses a CCD as a multipixel detector. We obtain the frequency spectrum of the scattered light by sweeping the heterodyne local oscillator frequency. Our detection scheme combines a high optical etendue (product of the surface by the detection solid angle) with an optimal detection of the scattered photons (shot noise). Using this technique, we measure, in vivo, the frequency spectrum of the light scattered through the breast of a female volunteer.
Assuntos
Mama/citologia , Refratometria/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Tomografia de Coerência Óptica/instrumentação , Transdutores , Desenho de Equipamento , Análise de Falha de Equipamento , Feminino , Humanos , Luz , Imagens de Fantasmas , Refratometria/métodos , Espalhamento de Radiação , Tomografia de Coerência Óptica/métodosRESUMO
We present a new detection scheme for acousto-optic tomography based on pulsed-wave ultrasound and illumination combined with heterodyne parallel speckle detection. This setup can perform tomographies inside several-centimeter-thick scattering samples. Test experiments confirm the suitability of this method for performing tomographies inside various types of optically scattering media, including liquids.
