Molecular spectroscopy is one of the most important technologies to identify molecules in science, chemistry, biology and even in security applications. Precision spectroscopy, optical communication, modern length and frequency measurements using references and secondary frequency standards respectively based on stabilised laser.

Modern microprocessor and control  technology as well as precision mechanics enabled us to developed a laser head based on off-the-shelf green laser modules, which are commonly used in laser pointer. In combination with the laser controller we obtain a temperature stability of ± 0.004 °C resulting in a pure single mode emission frequency with

a stability of ± 17.8 kHz which is more than enough for spectroscopic applications.

The green emission of the laser head is temperature tuned to fits to the well-known strong absorption line around 532 nm, resulting in a strong fluorescence emission. The coloured line spectrum shown on the right, has been taken by using the provided grating with 600 lines/mm. The grating is placed directly in front of a digital camera, tilted a bit up or down to catch the variety of coloured lines of the first or second order. Wow, not only the students  will be delighted to see the visible vibrational transitions with the naked eye, a tremendous contribution to better understand molecular physics.

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