| Popis: |
A miniaturized scanning mechanism is a crucial component in the creation of endoscopes for microscopic imaging. Several groups have developed resonant sca nners (e.g., spiral or Lissajous scan pa ttern), but these suffer from limitations in non-uniform spatial coverage and sampling time, in comparison to a raster scanner. Additionally, a resonant scanner lacks the ability to perform line-scan imaging, a crucial capability in measuring a variety of fast, dynamic physiological phenomena (e.g., blood flow, molecular diffusion, etc.). However, current miniaturized raster scanners are limited in terms of their physical dimensions and scan speed. We demonstrate a novel hybrid resonant/non-resonant miniaturized raster scanner, fabricated by mounting a double clad fiber onto two perpendicularly oriented piezo bimorphs. The fiber scanner has a total length of 2.6cm, a width/thickness 1mm, achieves 800 m fiber tip deflection for both the resonant and non-resonant axes, and allows for imaging at approximately 4 frames per second (512 lines per frame). An essentially uniform spatial coverage and sampling time can be achieved by utilizing the middle portion (e.g., middle 500 m) of the resonant scanning range. The small size allows for the fiber scanner to be easily packaged along with miniaturized lenses to form an endosc ope for microscopic imaging. We bonded a stiffening fiber alongside the vibrating fiber to break its cylindrical symmetry. Thus, only one vibration mode is excited, generating a purely linear spatial motion. In order to demonstrate the fiber scanners imaging capabilities we have taken transmission and fluorescence images, in which the double clad fibers inne r clad is used for fl uorescence collection. Keywords: fiber scanner, multiphoton endoscope, double clad fiber, raster scanner |
