fiber-laser-based ultrasound sensor for photoacoustic imaging

Especially for intra-vascular and endoscopic applications, sound and light imaging requires an ultrasound probe with a small size and high sensitivity.
In this paper, we propose a new approach based on small-
Fiber Laser.
The incident ultrasound applies pressure to the fiber laser and causes harmonic vibration of the fiber, which is detected by the frequency offset of the beating signal between two orthogonal polarization modes in the fiber laser.
This ultrasonic sensor makes noise.
Equivalent pressure at 50-40 paMHz bandwidth.
We have demonstrated this new ultrasonic sensor in optics.
Distinguish sound and light microscope
The axial and lateral resolutions are 48 μm and 3, respectively. 3u2009μm.
It appears to be in the economic and social field. 57u2009mm2.
The sensor has strong resistance to environmental interference, such as temperature changes, because --
The pattern is canceled between two orthogonal patterns.
The current optical fiber laser ultrasonic sensor is all-
Optical sound and light imaging
The fiber laser is manufactured by stamping two fiber Prague grating with wavelength matching (FBGs)
In the Er series
Yb co-doping fiber (EY-305, Fibercore).
Fiber grating refers to the Interior
The core cycle exponential modulation, formed by the diffraction of the phase shield, is illuminated by the use of a laser of 193 kbps nm excitation element.
Each grating acts as a distributed reflector with coupling strength k greater than 10 cm at the Prague wavelength, providing strong optical feedback for laser oscillation.
The grating period is 1053 nm and the corresponding reflection wavelength is . . . . . . = u2009 Λ u2009 1532 u2009 nm is refers to the effective refractive index of fiber.
This wavelength is the rare earth located in the absorption peaks of various places.
Ground-mixed optical fiber with maximum lumen gain.
The grating length is 6 and 5mm respectively.
The spacing of the grating is less than 0. 5u2009mm.
The output power of this laser is usually 500mw μ w, and the pump power at nm is 100 mw.