How to Build an SHG Apparatus
Over recent years, second-harmonic generation (SHG) microscopy has been well established as a microscopic imaging modality used in biophysics, biomedical optics, and biophotonics applications. It has already been widely demonstrated that SHG is a powerful technique for both cellular and tissue imaging. However, a commercial microscope exclusively dedicated to SHG imaging is still lacking. Very oen, SHG microscopes used in laboratory research are adapted from commercial (confocal or multiphoton) microscopes. However, for some applications, ex novo design is required to t the technical specications of the experiments to be performed. Several technical and experimental aspects have to be considered when designing a custom SHG microscope. is chapter aims to provide a technical guide to the researchers who want to build their own custom SHG microscope. is chapter is divided into three main parts. Starting from the possible solutions to be adopted for the mechanical system (Section 2.1), we then focus our attention on the most critical points of the experimental setup: the scanning (Section 2.2) and the detection (Section 2.3) systems. In each part of this chapter, we describe the most common congurations used in an experimental setup, highlighting their advantages and disadvantages, and focusing the attention of the reader on the most crucial aspects to be considered during both design and development. Finally (Section 2.4), we provide a short description of typical optical schemes used in SHG microscopy.