Intended institutions and users:
Physics education in Medicine
How it works ...
Consider a cube of Neodymium doped Yttrium Vanadate (Nd:VO4) with a length of the edge of 1 mm to which a KTP frequency doubler crystal with the same cross section but a length of 2 mm is bonded. Both opposite sides of the compound are are coated with a mirror forming an optical cavity for the radiation of 1064 nm. When pumped with a small laser diode in a ø3.6 mm housing green radiation is produced. With a typical pump power of 200-300 milliwatt at 808 nm green output power of around 10 milliwatt is obtained. Such a crystal compound (also termed as Green Laser Microchip GLM) allows the design of really small micro laser mainly used for laser imaging, green laser pointers, laser show, spectroscopy, medical diagnostics and a lot of other applications where the size of the laser source is of great importance.
Within this experiment we are using such a GLM and pumping it with the same setup as for the Nd:YAG laser (LE-0700). The GLM is mounted inside a 4 axes kinematic mount in order to align it to the focussed 808 nm pump radiation. As soon as the pump radiation hits the crystal green emission is produced. By aligning the crystal the optimum of green power will be observed. Due to the possibility of tuning the temperature and output power of the pump diode laser a series of measurements are carried out to demonstrate the typical quadratic relation between the green output and the fundamental power. The modulation capability of the diode laser driver allows the periodic switching on and off of the pump laser diode and to observe the "spiking" of the green radiation. Placing the provided RG1000 filter in front of the photodetector only the 1064 nm radiation will be observed. This facilitates the separate characterisation of the fundamental laser as well.