Acoustic wave detection probe and photoacoustic measurement apparatus provided with the same

摘要

In an acoustic wave detection probe provided with a light guide section that guides measuring light such that the measuring light is outputted toward a subject and an acoustic wave transducer that detects a photoacoustic wave generated in the subject by the projection of the measuring light, the light guide section includes a homogenizer that flat-tops an energy profile of the measuring light entered from the upstream side of the optical system, a light condensing member that condenses the measuring light transmitted through the homogenizer, and a bundle fiber which includes a plurality of optical fibers and is disposed such that the measuring light transmitted through the light condensing member enters from an entrance end of the bundle fiber.

主权项

1. An acoustic wave detection probe provided with a light guide section, and an acoustic wave transducer, wherein the light guide section comprises:
a homogenizer that flat-tops an energy profile of high energy measuring light entered the light guide section; a light condensing member that condenses the high energy measuring light transmitted through the homogenizer; and a bundle fiber which includes a plurality of optical fibers and is disposed such that the high energy measuring light transmitted through the light condensing member enters from an entrance end of the bundle fiber, wherein the homogenizer further diffuses the high energy measuring light; when the focal length of the light condensing member, the spread angle of the high energy measuring light when entering the homogenizer, and the diffusion angle of the homogenizer are taken as f, φ, and θ respectively, the light condensing member condenses the high energy measuring light such that a minimum beam diameter D defined by Formula 1 below satisfies Formula 2 below in relation to a diameter d of the bundle fiber; and the bundle fiber is disposed such that the high energy measuring light enters the bundle fiber with the beam diameter D being 0.8 d to 1.2 d;D=2.5·f·tan⁡((ϕ2)2+(θ2)2)Formula⁢⁢10.8⁢⁢d≦D≦1.2⁢⁢dFormula⁢⁢2 the light guide section comprises a beam expander optical system immediately before the entrance side of the homogenizer, the beam expander optical system having an expansion factor that conforms to angular apertures of the plurality of optical fibers so that the high energy measuring light is expanded to a beam diameter that conforms to the angular apertures of the plurality of optical fibers; the homogenizer is a light shaping diffuser in which small lenses are disposed randomly on one side of a substrate; the light guide section guides the high energy measuring light such that the high energy measuring light is outputted toward a subject and the acoustic wave transducer detects a photoacoustic wave generated in the subject by the proiection of the high energy measuring light; and the minimum beam diameter D is set to inhibit damage to the bundle fiber and eliminate the imbalance in the amount of energy between each light traveling through each optical fiber of the bundle fiber.