Fast interferometric second harmonic generation microscopy.

Stéphane Bancelin,Maxime Pinsard,Katherine Légaré,François Légaré,Maxime Rivard,Charles-André Couture,Cameron Brown

doi:10.1364/boe.7.000399

Abstract

We report the implementation of fast Interferometric Second Harmonic Generation (I-SHG) microscopy to study the polarity of non-centrosymmetric structures in biological tissues. Using a sample quartz plate, we calibrate the spatially varying phase shift introduced by the laser scanning system. Compensating this phase shift allows us to retrieve the correct phase distribution in periodically poled lithium niobate, used as a model sample. Finally, we used fast interferometric second harmonic generation microscopy to acquire phase images in tendon. Our results show that the method exposed here, using a laser scanning system, allows to recover the polarity of collagen fibrils, similarly to standard I-SHG (using a sample scanning system), but with an imaging time about 40 times shorter.

Highlights

In recent years, Second Harmonic Generation (SHG) microscopy has emerged as a powerful technique to probe non-centrosymmetric structures in biological tissues [1,2,3,4]
We address the second issue by implementing a fast Interferometric Second Harmonic Generation (I-SHG) imaging setup using the classical laser scanning system to reconstruct images of the sample
We reported here the first implementation of fast I-SHG microscopy using a scanning system based on galvanometric mirrors

Summary

Introduction

Second Harmonic Generation (SHG) microscopy has emerged as a powerful technique to probe non-centrosymmetric structures in biological tissues [1,2,3,4]. As SHG does not involve population transfer, it considerably reduces phototoxicity and is free from photobleaching [9,10]. This technique is highly specific for dense non-centrosymmetric media [3,11]. SHG microscopy appears to be a very sensitive and specific structural probe, both ex vivo and in vivo, of the macro-molecular architecture of a wide variety of tissues [12,13,14,15]

Methods

Results

Conclusion