A cost-efficient open source laser engine for microscopy

Abstract

Scientific-grade lasers are costly components of modern microscopes. For high-power applications, such as single-molecule localization microscopy, their price can become prohibitive. Here, we present an open-source high-power laser engine that can be built for a fraction of the cost. It uses affordable, yet powerful laser diodes at wavelengths of 405 nm, 488 nm and 640 nm and optionally a 561 nm diode-pumped solid-state laser. The light is delivered to the microscope via an agitated multimode fiber in order to suppress speckles. We provide the part lists, CAD files and detailed descriptions, allowing any research group to build their own laser engine.

Fluorescence Microscopy Light Source Review

“…Some drawbacks include the fact that there is only one wavelength per diode laser, they can be expensive, and they are sensitive to electrostatic charges. Open‐source options do exist for building and optimizing a more cost‐effective multi‐wavelength laser engine (Schroder, Deschamps, Dasgupta, Matti, & Ries, 2020). Lastly, white light lasers, as the name implies, cover a large part of the visible light spectrum (e.g., 470‐670 nm).…”

An economic, square-shaped flat-field illumination module for TIRF-based super-resolution microscopy

“…1, compatible with fibre-based laser engines (which are widely used in commercially-available or home-built setups [18]), 2, economic (1000 USD compared to 5000 USD for a beam shaper [10]), 3, compatible with TIRF illumination (owing to the small size of its core compared to widelyavailable square-core MMFs [13]), 4, optimized for square and rectangular large camera chips (owing to the square core and its ability to illuminate large FOVs), 5, compatible with highly-homogenous illumination (owing to improved mode scrambling compared to circular-core MMFs [13]).…”

“…More recently, a large square-core (150 μm x 150 μm) MMF was used to deliver a square flatfield illumination pattern for epi-based experiments but not applicable under TIRF imaging due to the large size of the fibre core diameter [13]. Imaging under TIRF can potentially give better signal-to-noise ratio as only the fluorophores bound on the surface within the evanescent field will selectively be excited.…”

“…1. it enables the full utilisation of the square and rectangular camera chips; 2. it delivers improved mode scrambling compared to circular-core fibres [13]. This is fundamentally important for minimizing the localization precision, improving stoichiometry quantification across the FOV, as well as for the faithful representation of the underlying biological samples.…”

Direct Supercritical Angle Localization Microscopy for Nanometer 3D Superresolution

“…The fiber output is mounted on a linear stage (SmarAct) in order to switch the illumination mode between total internal reflection (TIR), highly inclined and laminated optical sheet (HiLo) or epi-illumination. Alternatively, a custom laser engine can be used to obtain homogeneous illumination, as described previously 33 . After the illumination lens, the lasers are reflected on a 4x dichroic mirror (F73-410, AHF) before the objective (NA 1.7 APON 100XHOTIRF, Olympus).…”