High Collection Efficiency Optics for Surface Spectroscopy
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
The Cassegrainian mirror system has been adopted to collect effectively most of the light emitted by angles around 55o . For molecules or ions on a conducting surface it is only the normal component of the dipole which can emit light due to the effect of the dipole image in the conductor. The light emitted from an oscillating dipole on a conducting surface is most intense at an angle of 55o according to the classic electromagnetic theory. The Cassegrainian optical system, when designed properly, can be very effective in collecting most of this light. To collect effectively most of the light emitted by angles around the optimum 55o, it requires the use of proper aspheric mirrors, since the collected light is highly off axis. An example is shown in the figure.