A simple laser cooling and trapping apparatus for undergraduate laboratories

Abstract

We present detailed instructions for the construction of a pyramidal-style laser cooling and trapping apparatus. This scheme requires only a single beam, rather than the three pairs of orthogonal beams of the standard magneto-optical trap, which greatly simplifies the geometry and substantially reduces the cost. The trap is based largely on low-cost commercially available items and is simple to construct. It is remarkably insensitive to alignment and reliable to operate. Using a single laser beam with an intensity of 1.3 mW/cm2 we cool and trap more than 4 million rubidium atoms.

Design and construction of cost-effective tapered amplifier systems for laser cooling and trapping experiments

“…The ever-growing presence in the advanced undergraduate laboratory of the frequency-tunable external-cavity diode laser (ECDL), operating in single transverse and longitudinal mode with a linewidth of 1 MHz, is well documented. [1][2][3] These lasers have enabled the introduction of interesting topics in atomic and optical physics such as laser cooling and atom trapping, [4][5][6][7][8] electromagnetically induced transparency, 9,10 and novel techniques in Doppler-free and sub-natural linewidth spectroscopy. [11][12][13][14][15][16] It is well known that while ECDLs offer important advantages such as low cost, narrow linewidth, and wide tunability, they are limited in output power; after manipulations such as beamshaping, Faraday optical isolation, or fiber-coupling, one is typically left with less than 10 mW (Refs.…”

Measurement of sub-natural linewidth AC Stark shifts in cold atoms: An experiment for an advanced undergraduate laboratory

“…5 Building and operating a magneto-optical trap teaches students about frequency-narrowed tunable diode lasers, feedback circuitry for laser-locking, light polarization, optical pumping and hyperfine spectroscopy, magnetic field configurations, and aspects of high vacuum technology. Viewing a video of the slowly moving atoms diffusing outward from the trap, obtained by quickly turning off the magnetic field gradient in the trap thereby creating optical "molasses," is stimulates much student interest.…”

“…Students can also measure the number and temperature of the trapped atoms, and the trap-loading and loss rates as trap diagnostics while building the trap. 2,3,5 Once the magneto-optical trap is built, other striking and simple measurements can be done on the trapped cold atoms which illustrate basic physics concepts appropriate for upperlevel undergraduates. In this paper, we describe how we can measure sub-MHz AC Stark shifts, also known as light shifts, by Raman pump-probe spectroscopy, 6 implemented with the use of two inexpensive fast photodiodes connected to a simple hand-built amplifier circuit and a standard oscilloscope.…”

Construction and Characterization of a Tunable and Stabilized Diode Laser

“…Desde hace ya varios años los láseres de diodo son muy utilizados por su bajo costo, facilidad de operación y disponibilidad en distintas longitudes de onda (1)(2)(3) . Sin embargo, en ciertas aplicaciones donde la estabilidad y pureza espectral son relevantes poseen una serie de desventajas: son multimodo, tienen un ancho de banda grande, y la longitud de onda de emisión es muy sensible a cambios en la temperatura y la corriente.…”