Current Science

Lal Muanzuala ¹, Harish Ravi ¹, Karthik Sylvan ¹, Vasant Natarajan ¹

Affiliations
1 Department of Physics, Indian Institute of Science, Bengaluru 560 012, IN

Abstract

We demonstrate a straightforward technique to measure the linewidth of a grating-stabilized diode laser system-known as an external cavity diode laser (ECDL)-by beating the output of two independent ECDLs in a Michelson interferometer, and then taking the Fourier transform of the beat signal. The measured linewidth is the sum of the linewidths of the two laser systems. Assuming that the two are equal, we find that the linewidth of each ECDL measured over a time period of 2 μs is about 0.3 MHz. This narrow linewidth shows the advantage of using such systems for high-resolution spectroscopy and other experiments in atomic physics.

Keywords

Diode Laser, Grating Stabilization, Interferometer, Linewidth, Littrow Configuration.

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Ketan D. Rathod ¹, Vasant Natarajan ¹

Affiliations
1 Department of Physics, Indian Institute of Science, Bengaluru 560 012, IN

Abstract

We use the Ramsey separated oscillatory fields technique in a 400°C thermal beam of ytterbium (Yb) atoms to measure the Larmor precession frequency (and hence the magnetic field) with high precision. For the experiment, we use the strongly allowed ¹S₀→¹P₁ transition at 399 nm, and choose the odd isotope ¹⁷¹Yb with nuclear spin I = 1/2, so that the ground state has only two magnetic sublevels m_F=±1/2. With a magnetic field of 22.2 G and a separation of about 400 mm between the oscillatory fields, the central Ramsey fringe is at 16.64 kHz and has a width of 350 Hz. The technique can be readily adapted to a cold atomic beam, which is expected to give more than an orderof- magnitude improvement in precision. The signal-to- noise ratio is comparable to other techniques of magnetometry; therefore it should be useful for all kinds of precision measurements such as searching for a permanent electric dipole moment in atoms.

Keywords

Magnetometry, Oscillatory Fields, Precession Frequency, Ytterbium Atoms.

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Vasant Natarajan ¹

Affiliations
1 Department of Physics, Indian Institute of Science, Bangalore 560 012, IN

Abstract

No Abstract.

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