Introduction
The growing demands on spectral, spatial and temporal performance from the imaging hardware designed to support increasingly complex biological data collection, in state-of-the-art microscopy applications, are weighty. Light quality and consistency is critical to the sensitivity, discrimination, resolution, and the realized image quality. Sophisticated users are exploiting spectral complexity through the use of fluorophores that emit in ultraviolet, visible or near infrared wavelengths. The number and diversity of fluorescence probes keeps growing. Biological specimens are visualized via a broad array of sample formats including thick tissue sections on traditional microscope slides, microtitre plates with thousands of wells, microarrays of genomic materials with hundreds of thousands of spots, and a diverse range of custom “chips” which can contain fluidic channels or electrochemical sensors, to name a few. While widefield fluorescence microscopy techniques have long been implemented with fluorphore families, hardware developments are still required to overcome the physical constraints inherent to such sample complexity. Optically pooled screening and single molecule localization microscopy (MERFISH) are techniques designed to exploit label diversity for so-called spatial biology applications. Structured illumination microscopy (SIM) and spinning-disk confocal microscopy are pushing the physical boundaries of subcellular resolution and sample penetration depth. Yet the lasers utilized to engage in such complex microscopy represent their own challenges. Selecting a set of lasers from the variety of source technologies, controlling their modal behavior, taming short and long term stability, and managing alignment on a configurable optical table presents a non-trivial challenge and can be distracting from the biologists’ primary focus. To facilitate such hardware mastery, Lumencor offers the CELESTA Light Engine.
Lumencor’s CELESTA Light Engine (CELESTA) consists of seven individually addressable solid-state lasers (Table 1) from a larger group of available laser sources. The CELESTA can house up to seven lasers, each delivering ~800 mW at the output end of a downstream optical fiber. One of the most operationally important features of the CELESTA is that the light output characteristics of all seven lasers are consistent in spatial and temporal respects; only the wavelengths differ for each of the CELESTA sources. This paper focusses on the temporal characteristics of CELESTA light output, presenting typical data over different timescales and using a variety of photometric detectors.
