Bessel‐beam illumination in dual‐axis confocal microscopy mitigates resolution degradation caused by refractive heterogeneities. Issue 1 (26th September 2016)

• Record Type: Journal Article
• Authors: Chen, Ye; Glaser, Adam; Liu, Jonathan T. C.
• Is Part Of: Journal of biophotonics. Volume 10:Issue 1(2017)
• Page Start: 68
• Page End: 74
• Publication Date: 2016-09-26
• Subjects: confocal microscopy -- beam‐steering and distortion -- resolution degradation -- Bessel beams; Photonics -- Periodicals; Optical materials -- Periodicals; Optics -- Periodicals; Medical instruments and apparatus -- Periodicals; 621.3605
• DOI: 10.1002/jbio.201600196
• Languages: English
• ISSNs: 1864-063X

Abstract

Abstract : One of the main challenges for laser‐scanning microscopy of biological tissues with refractive heterogeneities is the degradation in spatial resolution that occurs as a result of beam steering and distortion. This challenge is particularly significant for dual‐axis confocal (DAC) microscopy, which achieves improved spatial‐filtering and optical‐sectioning performance over traditional confocal microscopy through off‐axis illumination and collection of light with low‐numerical aperture (NA) beams that must intersect precisely at their foci within tissues. DAC microscope image quality is sensitive to positional changes and distortions of these illumination‐ and collection‐beam foci. Previous studies have shown that Bessel beams display improved positional stability and beam quality than Gaussian beams when propagating through tissues with refractive heterogeneities, which suggests that Bessel‐beam illumination may enhance DAC microscopy of such tissues. Here, we utilize both Gaussian and Bessel illumination in a point‐scanned DAC microscope and quantify the resultant degradation in resolution when imaging within heterogeneous optical phantoms and fresh tissues. Results indicate that DAC microscopy with Bessel illumination exhibits reduced resolution degradation from microscopic tissue heterogeneities compared to DAC microscopy with conventional Gaussian illumination. Abstract : The propagation‐invariant and self‐reconstructing features of Bessel beams have been shown to benefit volumetric microscopy of tissues with refractive heterogeneities. This study examined the resolution degradation that occurs when performing dual‐axis confocal (DAC) microscopy within tissues using Gaussian or Bessel illumination. Results indicate Bessel beams are useful for preserving resolution in DAC microscopy, in which tissue‐imaging performance is sensitive to positional changes and distortions of off‐axis illumination and collection beams.