Fast optical cooling of nanomechanical cantilever with the dynamical Zeeman effect

Abstract

We propose an efficient optical electromagnetically induced transparency (EIT) cooling scheme for a cantilever with a nitrogen-vacancy center attached in a non-uniform magnetic field using dynamical Zeeman effect. In our scheme, the Zeeman effect combined with the quantum interference effect enhances the desired cooling transition and suppresses the undesired heating transitions. As a result, the cantilever can be cooled down to nearly the vibrational ground state under realistic experimental conditions within a short time. This efficient optical EIT cooling scheme can be reduced to the typical EIT cooling scheme under special conditions.

Efficient cooling of quantized vibrations using a four-level configuration

“…which is similar to the square-law style of the cooling laser strength in the EIT cooling scheme [18]. Similar to the asymmetric cooling scheme, the fluctuation spectra in symmetric counterpart are obtained and plotted in Fig.…”

“…Magnetic field gradient, in addition to laser irradiation, is required to couple the internal to the vibrational degrees of freedom of the solidstate system. Besides, due to existence of an additional decay to a metastable level in the nNV center [17], a pumping process in addition to usual cooling operations is demanded [18]. Even with all these considerations, however, a three-level structure employed in a nNV center is proven to be not qualified for a perfect cooling since the first-order blue sideband transition cannot be fully eliminated [18][19][20].…”

“…One of our schemes with a modified Λ-type configuration is based on a dynamical EIT [10,18] plus a Stark-shift gate [15,19], which is called briefly as the asymmetric cooling method. The other, called shortly as the symmetric cooling method, combines the Λ-type with V -type configurations, which yield double Starkshift gates.…”

“…The other, called shortly as the symmetric cooling method, combines the Λ-type with V -type configurations, which yield double Starkshift gates. As we know, most of the cooling schemes proposed so far are based on Λ-type three-level systems [1,10,18,21], rather than the V -type three-level configuration [20] , due to the fact that the latter with two upper levels is more susceptible to dissipation. However, as shown below, a better cooling could be achieved if we elaborately combine the Λ-type and V -type configurations and have them interfered with each other.…”

“…with Ω/ω k = 1.5. In each panel, the dashed-dotted, dotted, dashed and solid curves represent the asymmetric cooling, EIT [18], Stark-shift-gate [15] and the symmetric cooling schemes, respectively. Here we suppose zero-temperature environment and the decay rate of the internal levels to be Γ = 150λ.…”