Our New LED Based Flash Photolysis System
The Cairn Optoflash is the latest member of the Cairn OptoLED family. It uses our established LED head and microscope coupling designs, but is optimised for short-term intense illumination. This makes it particularly suitable for the photoactivation of “caged” neurotransmitter or other compounds, and for the important emerging application of channel rhodopsin activation.
The maximum current through an LED is generally limited by thermal considerations. Efficient heat removal from the device is only a partial solution, as the thermal resistance between the LED chip and its packaging always constitutes a significant bottleneck. Even so, the chip temperature rise on application of current still takes some milliseconds, so for illumination periods on this timescale, currents substantially higher than the steady-state maximum can safely be passed.
All our LED heads contain protection networks to limit both the transient and steady-state current to safe levels for that particular device. The LED heads intended for this particular application have had their protection networks optimised for short-term illumination periods, so as to maximise the intensity during a flash.