Descripción of activity “Tunable laser construction and its application”.

This activity consists in the construction and assembling of an experimental system based on a tunable diode laser and a vapor cell. This laser that has a lot of applications in experimental optics wil be completely assembled by our Chapter. Afterwards we will show in a period of two weeks a set of experiments showing the Doppler feature and saturated absorption. The experiments will be showed to other physics and engineering students with a previous inscriptions via webpage in a two weeks period. The exhibition will be personalized.

Summary 2008

Images

October 2th 2008

we installed the lens in front of the diode laser. We wired and powered the laser correctly. Any mistake would have burned our laser!!! Afterwards we adjusted the lens which has a focal length of f=4.5 mm. After many trials and errors and corrections of the thread of the tube that contains the diode and the lens we obtained a well collimated red laser beam. Here is a photo of our first laser emision at 671 nm. Congratulations to Jorge Tapia and Cristian Moreno.

Wednesday, October 8th 2008
We have aligned the lens in front of the laser diode. Due to the small size of the lens, short thread and small focal distance (4.5 mm) we have done a very careful work to obtain a well collimated laser beam. The colour of the laser emission was dark red at 671 nm.
Impressive!

Thuersday, October 9th 2008

We installed the diffraction grating in front of the lens. The vertical alignement was straightforward. We displaced the grating mount backwards in order to avoid that the beams hits the lens mount. All the previous designs made by our Chapter were correctly made: The laser beam passed close to the lens mount and through the hole at the laser box. Congratulations to the team!
Afterwards we installed a Thorlabs SP2 spectrometer and guided the laser light into the spectrometer by means of a glass fiber. We could see the spectra on the monitor of our notebook. It was placed very close to 671 nm.
We displaced the wavelength to 671nm moving the grating in the left right direction. This was a confirmation that the grating was doing its jobto tune the laser. We observed also the mode hops as we exaggerated the displacement of the grating.

Spectra, and Interferograms will be added soon to this wabpage!!

Friday, October 10 th 2008

The laser was showed to nearly 10 students of the Modern Spectroscopy Course and other friends. We installed the temperature controller. It worked fine. The temperature was stabilized at 20 degrees, very close to the room temperature as a first setting. The controller was stabilizing very rapidlly the laser temperature.

Laser Measurements and results (esp)

Espectrómetro y longitud de onda de Laser 671 nm

Los datos aquí mostrados, fueron adquiridos mediante un espectrómetro Thorlabs SP2-USB (rango spectrometer 500nm to 1000nm aprox.) con su respectivo programa computacional de adquisición de datos. Para medir, se hace incidir la luz láser sobre la fibra óptica, conectada al espectrómetro el cual a su vez esta conectado al puerto USB del computador. El programa de adquisición de datos entrega un grafico en tiempo real de intensidad de luz en función de la longitud de onda.

Es posible cambiar la longitud de onda de la radiación que el diodo láser proporciona, a partir del posicionamiento optimo de la red de difracción para que la retroalimentación sea correcta. Los siguientes gráficos muestran 3 distintas longitudes de onda obtenidas.