Modulated light-wave fluctuations in the Stark-pulse technique

A. I. Alekseev, Ashat M. Basharov

Felix R. Graf, Bernd H. Plagemann, Alois Renn +2 more

Using Stark-pulse-modulated photon echoes, we observe a novel type of rephasing phenomenon in a Eu(3+) - and Pr(3+) -codoped Y(2)SiO(5) crystal. By adjusting the Stark pulse during the rephasing and dephasing periods one can observe a full recovery of the photon echo, corresponding to perfect dephasing-rephasing balancing of the perturbations. We propose to use this effect as a spectroscopic technique to distinguish between reversible and irreversible Stark interactions.

V. M. Semibalomut, R. I. Sokolovskiǐ

Michael D. Stenner, Daniel J. Gauthier

Summary form only given. A recent technique for creating "fast" light pulses (i.e. pulses of light having group velocity greater than c or less than zero) uses a continuous-wave bichromatic Raman pump laser beam to tailor the dispersion properties of an atomic vapor. We have discovered a number of effects that impose limits on fast-light propagation as the gain increases. Most important is the modulation instability, a nonlinear effect that can lead to temporal modulation of intense continuous-wave laser fields. We discuss the induced modulation instability in the context of high-gain bichromatically driven atomic systems, specifically in the context of fast-light pulse propagation. We further discuss the practical limitations that the induced modulation instability imposes on this method for creating faster-than-c pulses.

V. T. Bykovskii, Yu. S. Oseledchik, V. G. Khaladzhi

Ming‐Da Huang, Zhan-Feng Jiang, Hongyi Chen +5 more

The range and speed of a moving object can be ascertained using the sensing technique known as light detection and ranging (LiDAR). It has recently been suggested that quantum LiDAR, which uses entangled states of light, can enhance the capabilities of LiDAR. Entangled pulsed light is used in prior quantum LiDAR approaches to assess both range and velocity at the same time using the pulses' time of flight and Doppler shift. The entangled pulsed light generation and detection, which are crucial for pulsed quantum LiDAR, are often inefficient. Here, we study a quantum LiDAR that operates on a frequency-modulated continuous wave (FMCW), as opposed to pulses. We first outline the design of the quantum FMCW LiDAR using entangled frequency-modulated photons in a Mach-Zehnder interferometer, and we demonstrate how it can increase accuracy and resolution for range and velocity measurements by $\sqrt{n}$ and $n$, respectively, with $n$ entangled photons. We also demonstrate that quantum FMCW LiDAR may perform simultaneous measurements of the range and velocity without the need for quantum pulsed compression, which is necessary in pulsed quantum LiDAR. Since the generation of entangled photons is the only inefficient nonlinear optical process needed, the quantum FMCW LiDAR is better suited for practical implementations. Additionally, most measurements in the quantum FMCW LiDAR can be carried out electronically by down-converting optical signal to microwave region.