Stabilization and time resolved measurement of the frequency evolution of a modulated diode laser for chirped pulse generation

TL;DR

This paper presents a method for generating and stabilizing chirped laser pulses with controlled frequency evolution, enabling precise atomic state manipulation in quantum experiments.

Contribution

The authors introduce a novel experimental approach for producing and stabilizing frequency-chirped laser pulses using sinusoidal modulation and beat signal analysis.

Findings

Achieved stable, controllable frequency sweeps in nanosecond laser pulses.

Demonstrated high-speed frequency modulation suitable for atomic state control.

Implemented a simple stabilization method using beat signals with an atomic reference.

Abstract

We have developed experimental methods for the generation of chirped laser pulses of controlled frequency evolution in the nanosecond pulse length range for coherent atomic interaction studies. The pulses are sliced from the radiation of a cw external cavity diode laser while its drive current, and consequently its frequency, are sinusoidally modulated. By the proper choice of the modulation parameters, as well as of the timing of pulse slicing, we can produce a wide variety of frequency sweep ranges during the pulse. In order to obtain the required frequency chirp, we need to stabilize the center frequency of the modulated laser and to measure the resulting frequency evolution with appropriate temporal resolution. These tasks have been solved by creating a beat signal with a reference laser locked to an atomic transition frequency. The beat signal is then analyzed, as well as its spectral sideband peaks are fed back to the electronics of the frequency stabilization of the modulated laser. This method is simple and it has the possibility for high speed frequency sweep with narrow bandwidth that is appropriate, for example, for selective manipulation of atomic states in a magneto-optical trap.