Manipulation of ultracold Rb atoms using a single linearly chirped laser pulse

Amplification of pulsed light with arbitrary frequency chirps on nanosecond timescales

We have developed a system for producing amplified pulses of frequency-chirped light at 780 nm on nanosecond timescales. The system starts with tunable cw laser light and employs a pair of fiber-based phase modulators, a semiconductor optical amplifier, and a tapered amplifier to achieve chirp rates exceeding 3 GHz/10 ns and peak powers greater than 1 W. Driving the modulators with an arbitrary waveform generator enables arbitrary chirp shapes, such as two-frequency linear chirps. We overcome the optical power limitations of the modulators by duty cycling and avoid unseeded operation of the tapered amplifier by multiplexing the chirped pulses with "dummy" light from a separate diode laser.

Control of temporal shape of nanosecond long lasers using feedback loops

We present developments in the control of the temporal pulse shape of nanosecond lasers. An active feedback loop between a regenerative amplified laser's output and input was controlled in order to obtain the desired pulse shape. We used several algorithms to achieve this and the differences caused by the target pulse shape and duration are compared. It is found that the algorithm based on the ratio of the target pulse shape and measured pulse profile provides the most robust solution. The methods proposed here can be used to obtain any pulse shape with minimal knowledge of the laser amplification system.

Nanosecond pulse shaping at 780 nm with fiber-based electro-optical modulators and a double-pass tapered amplifier

We describe a system for generating frequency-chirped and amplitude-shaped pulses on time scales from sub-nanosecond to ten nanoseconds. The system starts with cw diode-laser light at 780 nm and utilizes fiber-based electro-optical phase and intensity modulators, driven by an arbitrary waveform generator, to generate the shaped pulses. These pulses are subsequently amplified to several hundred mW with a tapered amplifier in a delayed double-pass configuration. Frequency chirps up to 5 GHz in 2 ns and pulse widths as short as 0.15 ns have been realized.

Stimulated Raman spectroscopy with 0π pulses

We developed a new variant of stimulated Raman spectroscopy with shaped short pulses, applicable to multiscattering media. The technique is based on the spectral modulation of the laser pulse due to the Raman scattering and may have a broad range of applications from spectroscopy and pathogen detection to microscopy.