Confocal microscopy using an InGaN laser diode at 406nm

We report on the application of a novel blue laser diode source to confocal microscopy. The source has the potential to be a replacement for argon lasers in a range of fluorescence based imaging systems. It has been demonstrated that with the use of a minimal number of optical components, high quality confocal images can be obtained from laser diodes operating around 406nm. Improvements in image quality through the use of anamorphic prisms to modify the beam profile have been investigated. Living mammalian cells stained with a range of biologically significant compounds have been imaged with high resolution. The stains excited range from fluorescein based compounds to green fluorescent protein. Through the use of the absorption wings a wide range of shorter wavelength fluorophores have been excites, including those more normally excited using UV laser systems. It is expected that this will lead to reduced photo-toxicity within the sample and conventional rather than UV transmitting objective lenses can be used.