Technology
Multiphoton Confocal Microscopy
The SP2 confocal microscope has been upgraded to allow multiphoton excitation. A Spectra-Physics Mai-Tai laser, now coupled to the microscope can be tuned to any wavelength between 700 and 920nm. The new external non-descanned detectors can collect even very weak fluorescent signals. For bright samples, the confocal detectors can still be used if one needs to separate more than two fluorescent labels. Multiphoton excitation is best suited to live samples where visible radiation must be kept to a minimum, or where UV excitation is required but cannot be used without causing cell damage. Multiphoton excitation is also used for scanning deep into tissues or organs, where scattering of light reduces signal intensity.