Nd:YAG crystal absorption-emission experiment

This set allows introducing all the essential concepts for understanding the processes involved in the Laser effect. It can be complemented by mirrors to create a resonator and thus address the amplification and the Nd:YAG Laser cavity. The laser diode, equipped with a thermoelectric cooling device, is used to pump an Nd:YAG crystal. The laser diode controller allows modifying parameters such as the temperature and current of the pumping diode, as well as modulating it in intensity. Themes covered: - Einstein coefficient, absorption, spontaneous and stimulated emission - Laser diode, threshold and efficiency curve of the diode - Wavelength dependence on the temperature of the laser diode - Optical pumping, absorption optimization - Nd:YAG crystal absorption - Fluorescence decay, excited state lifetime - Interferential filter and high-pass filter Principles and objectives: Absorption and stimulated emission by optical pumping are important processes in the Laser effect. Optical pumping allows population inversion, and its efficiency depends on the absorption of the active medium and possible emission transitions within it. By adjusting the temperature of the laser diode and thus changing its wavelength, it is possible to optimize the absorption of the Nd:YAG crystal and therefore the efficiency of optical pumping. The spectral absorption profile of the crystal can thus be obtained. The de-excitation of the medium generates fluorescence that is collected by suitable optics and measured by a photodiode after being filtered (1064 nm). The excited state lifetime is thus measured.

Composition:
▪ 1 optical rail 0.5 m, with graduated ruler
▪ 1 100 mW - 808 nm laser diode, temperature stabilized with rotatable support on slider
▪ 1 laser diode controller (temperature, current, modulation)
▪ 1 beam shaping optics for laser beam with support on slider
▪ 1 Nd:YAG crystal in mount with 2-axis adjustment and support on slider
▪ 2 beam shaping optics for fluorescent beam with support on slider
▪ 1 high-pass filter
▪ 1 interferential filter (1064 nm)
▪ 1 filter support on slider
▪ 1 PIN photodiode with support on slider
▪ 1 IR visualization card (800-1600 nm)
▪ 2 pairs of Laser safety glasses
▪ 1 set of experiments instructions (in English)