Precise pulse shaping for quantum control of strong optical transitions

Abstract

Advances of quantum control technology have led to nearly perfect single-qubit control of nuclear spins and atomic hyperfine ground states. In contrast, quantum control of strong optical transitions, even for free atoms, are far from being perfect. Developments of such quantum control appears to be limited by available laser technology for generating isolated, sub-nanosecond optical waveforms with 10's of GHz programming bandwidth. Here we propose a simple and robust method for the desired pulse shaping, based on precisely stacking multiple delayed picosecond pulses. Our proof-of-principal demonstration leads to arbitrarily shapeable optical waveforms with 30 GHz bandwidth and 100 ps duration. We confirm the stability of the waveforms by interfacing the pulses with laser-cooled atoms, resulting in “super-resolved” spectroscopic signals. This pulse shaping method may open exciting perspectives in quantum optics, and for fast laser cooling and atom interferometry with mode-locked lasers.

Atomic spin-wave control and spin-dependent kicks with shaped subnanosecond pulses

“…[31], the improvement may be achieved with a combined effort of stronger input, wider modulation and tighter laser focus. As a promising alternative, the control pulses may also be generated with mode-locked lasers [35,36,[67][68][69][70] with orders of magnitudes enhanced peak power and pulse bandwidth. Here we notice that for a same control operation, the required pulse peak power and energy scales with 1/τ 2 c and 1/τ c respectively.…”

“…In addition, the control strength Ω c 1/τ c and the modulation bandwidth are also upper-bounded too to avoid uncontrolled light shifts and multi-photon excitations. Therefore, for the purpose of precisely and flexibly control of dipole spin waves with mode-locked lasers, it appears shaping picosecond pulses are more preferred than shaping ultrafast pulses [35,67,71,72] for generating nearly resonant pulses with a suitable duration and modulation bandwidth.…”

Spinor matterwave control with nanosecond spin-dependent kicks

“…Precise control of the spinnor matterwave with light requires carefully tailored light-atom interactions. Unlike microwave control of magnetic spins, quantum control of macroscopic matterwave with lasers is substantially more demanding on the intensity-error resilience [48,61]. To meet the high fidelity requirements by the next generation quantum technology, particularly on macroscopic samples, implementation of error-resilient quantum techniques [15][16][17] are likely required.…”

Intense, wideband optical waveform generation by self-balanced amplification of fiber electro-optical sideband modulation

“…Since strong transitions have coherence time radiatively limited to tens of nanoseconds, their full and coherent control requires optical waveforms with modulation bandwidth at the GHz level beyond standard CW modulation technology. Although ultrafast pulses can have bandwidth beyond THz, the pulse spectral brightness is usually too weak to efficiently drive the narrow transitions [19][20][21].…”

“…Efforts have been made to generate intense, coherent optical waveforms with GHz modulation bandwidth for atomic physics applications [22]. For example, coherent pulse trains with short inter-pulse delays are generated in the time domain to excite atoms efficiently [11,21]. Fiber electro-optical modulators (fEOM) with ∼10 GHz bandwidths are exploited to transfer modulation from microwaves to light [18,[22][23][24][25][26].…”