Enhanced volumetric imaging in 2‐photon microscopy via acoustic lens beam shaping. Issue 2 (25th July 2017)

• Record Type: Journal Article
• Authors: Piazza, Simonluca; Bianchini, Paolo; Sheppard, Colin; Diaspro, Alberto; Duocastella, Martí
• Is Part Of: Journal of biophotonics. Volume 11:Issue 2(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-07-25
• Subjects: acousto‐optic lens -- adaptive optics -- optofluidics -- three‐dimensional imaging -- two‐photon microscopy; Photonics -- Periodicals; Optical materials -- Periodicals; Optics -- Periodicals; Medical instruments and apparatus -- Periodicals; 621.3605
• DOI: 10.1002/jbio.201700050
• Languages: English
• ISSNs: 1864-063X

Abstract

Abstract : Three‐dimensional imaging at high‐spatiotemporal resolutions and over large penetration depths is key for unmasking the dynamics and structural organization of complex biological systems. However, the need to axially shift the focus, with consequent limitations in imaging speed, and signal degradation at large depths due to scattering effects, makes this task challenging. Here, we present a novel approach in 2‐photon excitation microscopy that allows fast volumetric imaging and enhanced signal‐to‐background (S/B) in thick tissue. Our technique is based on ultrafast beam shaping at each pixel by means of an acoustic optofluidic lens. Shaping the excitation beam with different phase profiles enables both high‐speed axial focus shifting, for continuous volumetric imaging, and controlled aberrated imaging, advantageous for out‐of‐focus background removal. We provide a theoretical description of our approach, and demonstrate volumetric imaging of neuronal cells from a mouse brain slice with enhancements in S/B up to a factor of 10 over a depth of 600 μm. Abstract : A simple technique for fast volumetric imaging and enhanced signal‐to‐background (S/B) in 2‐photon microscopy is presented. The approach uses an acoustic optofluidic lens to shape the excitation beam on a pixel‐by‐pixel basis. Control of the phase induced by the lens enables both fast axial focus scanning, for continuous volumetric imaging, and controlled aberrated imaging, suitable for background removal. The high temporal resolution and enhanced penetration depth capabilities of the method are demonstrated by imaging mouse brain tissue.