Using either the presence of natural fluorescence (autofluorescence), fluorescent proteins in biological samples or more commonly by the use of fluorescent dyes to stain the sample prior to viewing, imaging a sample using fluorescence can greatly enhance the resolution over other microscopy methods. It is widely used in life sciences to image cell or protein structures, microtitre plate analysis and high throughput screening analysis. Fluorescence Lifetime IMaging spectroscopy (FLIM) uses similar principles to monitor fluorescence decay rather than intensity benefiting from reduced scatter interference.
Cyanine, Atto and azo dyes amongst others are excited by laser light and emit light of a longer wavelength allowing fine structures to be made visible below the diffusion limited resolution of standard confocal microscopy. The vast array of available dyes allows highly specific structures to be imaged when partnered with excitation light of the right wavelength. This has traditionally been dominated by diode lasers, due to the wider array of wavelengths available with this technology, but as the technology of DPSS lasers improves, wavelengths well matched to the application are now coming on to the market, and offering greatly improved stability in power and wavelength, as well as a far narrower linewidth, reducing the requirement for expensive filter sets and allowing imaging of fluorescence wavelengths far closer to the excitation wavelength.
With required power in the order of milliwatts, compatibility and ease of use becomes important, together with the availability across the wavelength spectrum and spectral stability. Many of our lasers are suited to this area due to their stability, size and easy integration into any microscope system, including the use of fibre coupling and all can be controlled by software or manually by controls on the power supply.