Stark-chirped Rapid Adiabatic Passage Research Articles

Robust cascaded frequency conversion through shortcuts to adiabaticity

We propose a cascaded frequency conversion technique based on Stark-chirped rapid shortcuts to adiabatic passage (SCRSAP). The implementation of this technique corrects the coupling function in Stark-chirped rapid adiabatic passage (SCRAP) technique by means of shortcuts to adiabaticity (STA) counter-diabatic (CD) driving. The results of numerical simulations show that SCRSAP technique allows efficient frequency conversion at lower pump laser intensity and a wider range of delay parameters than SCRAP technique, and the STA technique improves the robustness of the process to temperature and signal frequency variations in adiabatic frequency conversion.

Efficient two-process cascaded frequency conversion based on Stark-chirped rapid adiabatic passage

A comprehensive study of two simultaneous three wave mixing processes and second harmonic generation, followed by difference frequency generation, based on Stark-chirped rapid adiabatic passage (SCRAP), is presented. The complete conversion from the input pump laser to the signal laser and the idler laser pair is achieved without exciting intermediate laser, and the frequencies of the signal laser and the idler laser are close to the input pump laser. This process is similar to the Stark-chirped rapid adiabatic passage for atomic population transfers, and we bring the analogy from atomic systems to our field of nonlinear optics. A two-process cascaded frequency conversion model based on Stark-chirped rapid adiabatic passage is established, and we analytically obtain the adiabaticity condition required for complete conversion. The research results show that this theoretical model results in a large tuned wavelength of about 380 nm with almost complete conversion of the input pump laser to the signal laser and idler laser.

Wavelength conversion of KTP crystal based Stark-chirped rapid adiabatic passage

The nonlinear wavelength conversion can generate the laser wavelengths which are not directly available, thereby broadening the laser spectrum range. However, the phase mismatch greatly limits the development and application of nonlinear optical technology. The wavelength conversion schemes in a manner analogous to population transfer in atomic rapid adiabatic passage, stimulated Raman adiabatic passage (STIRAP), and Stark chirped rapid adiabatic passage (SCRAP) provide feasible solutions for efficient and broadband wavelength conversion. The SCRAP uses the Stark shift caused by the Stark field to generate energy level crossings, therefore, the population in initial state can be efficiently converted into the target state. It does not require the two-photon resonance, and can be applied to multi-photon transition. In this paper, by approximate analogy to the adiabatic population theory, a wavelength conversion model with the KTP crystals based SCRAP is established, the influence of the coupling delay parameters, width parameters, pump intensity, temperature, and incident wavelength on the conversion process are systematically studied. The results show that the signal laser energy can be almost converted into output laser energy, while the intermediate laser energy is kept extremely low in the conversion process. The conversion process is sensitive to changes in coupling delay parameters, width parameters, and pump intensity. The farther away fromits optimal value the coupling delay parameter, the lower the conversion efficiency is. When the width parameter <inline-formula><tex-math id="M1">\begin{document}$ d_2^2 $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M1.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M1.png"/></alternatives></inline-formula> is fixed, as the width parameter <inline-formula><tex-math id="M2">\begin{document}$ d_1^2 $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M2.png"/></alternatives></inline-formula> increases, the conversion efficiency first increases to a maximum value, and then slowly decreases. At the same time, the greater the value of the width parameter <inline-formula><tex-math id="M3">\begin{document}$ d_2^2 $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="11-20210887_M3.png"/></alternatives></inline-formula>, the greater the achievable maximum conversion efficiencies, and the greater the bandwidth that can achieve high-efficiency wavelength conversion. The conversion efficiency increases as the pump intensity increases. When the conversion efficiency value reaches a maximum value, the increase in pump intensity has almost no effect on the conversion efficiency. However, changes in temperature and incident wavelength have little effect on the conversion efficiency. The above research can provide a theoretical basis for the acquisition of ultraviolet to mid-infrared light sources and the manufacture of photonic devices.

Supersymmetry-enhanced stark-chirped rapid-adiabatic-passage in multimode optical waveguides.

We propose a method to efficiently pump an excited mode of a multimode optical waveguide starting from a fundamental-mode input by combining Stark-Chirped Rapid Adiabatic Passage (SCRAP) and Supersymmetry (SUSY) transformations. In a two-waveguide set, we implement SCRAP by modulating the core refractive index of one waveguide, which is evanescently coupled to its SUSY partner. SCRAP provides an efficient transfer of light intensity between the modes of different waveguides, while SUSY allows to control which modes are supported. Using both techniques allows to achieve fidelities above 99% for the pumping of the excited mode of a two-mode waveguide. Additionally, we show that SCRAP can be exploited to spatially separate superpositions of fundamental and excited modes, and how SUSY can also improve the results for this application.

Synthesis of white laser source based on nonlinear frequency conversion with stimulated Raman adiabatic passage

This paper proposes a theoretical scheme to synthesize white laser source based on the cascaded sum frequency generation (CSFG) model with stimulated Raman adiabatic passage (STIRAP). In the CSFG model, the signal laser, intermediate laser and output laser correspond to red, green and blue (RGB) lasers respectively. The results show that in general the red laser is completely converted to the blue laser, and there is no apparent intermediate green laser. Moreover, under the counterintuitive order, the pump parameters have a wider adjustment range of system conversion efficiency than the coupling delay parameters. We synthesize the white laser source through the following steps. First, we change the pump intensity to roughly adjust the conversion efficiency of the system, and then vary the coupling delay parameters to fine-tune RGB lasers output power ratio. Compared with the scheme based on frequency conversion with Stark-chirped rapid adiabatic passage to synthesize white laser source, the RGB lasers output of the new scheme can achieve better stability. The results of the investigation can provide a theoretical foundation for the research of novel optical devices.

Stark-shift-chirped rapid-adiabatic-passage technique in tripod systems

We show that the technique of Stark-chirped rapid adiabatic passage (SCRAP), can be implemented in tripod quantum systems. We propose a scheme for coherent superposition among two ground states via Stark-shiftchirped rapid adiabatic passage technique in a tripod system. Tripod-SCRAP uses four laser pulses: an intense far-off-resonance Stark laser pulse modifies the transition frequency between the states by Stark shifting their energies and three nearly resonant pump, Stokes, and control laser pulses that fractionally transfer the population between the ground states via adiabatic passage. In our scheme, the pulse duration of the pump pulse must be larger than the pulse duration of the Stokes and control pulses, although with a smaller amplitude, and the atom encounters with the pump, Stokes, control, and Stark laser pulses with counterintuitive order (Stokes pulse arrives before the rest of the pulses). This technique can be applied to one-photon as well as multiphoton transitions and it is not necessary to vanish the pulses (pump and Stokes) simultaneously and it is a powerful alternative tool for f-STIRAP and tripod-STIRAP techniques at least when inhomogeneous broadenings are included. inhomogeneous broadening. This technique is robust against moderate variations in the intensities of the laser pulses,in detunings, and in delays between the pulses.

Efficient cascaded wavelength conversion under two-peak modulated Stark-chirped rapid adiabatic passage via grating structures

In this paper, we demonstrate a domain inversion crystal structure to study the cascaded three-wave mixing process in a two peak Stark-chirped rapid adiabatic passage. We have achieved efficient wavelength conversion, which can be performed in intuitive order and counterintuitive order. The requirement of crystal is reduced and the flexibility of structure design is improved. When the conversion wavelength is fixed, increasing the coupling coefficient between the two peaks can reduce the intensity of the intermediate wavelength while maintaining high conversion efficiency. Compared with the cascaded wavelength conversion process based on stimulated Raman rapid adiabatic passage, the two-peak modulated Stark-chirped rapid adiabatic passage has a larger convertible wavelength bandwidth. This scheme provides a theoretical basis for obtaining mid-infrared laser source via flexible crystal structure.

Population transfer in a nonlinear three-level Λ-system by Stark - chirped rapid adiabatic passage

We propose the use of the Stark-chirped rapid adiabatic passage (SCRAP) method to induce a complete population transfer in a nonlinear three-level Λ-type system (nl-SCRAP). We also use the nl-SCRAP method for creating stable diatomic ground molecular Bose–Einstein condensates (BECs) from atomic BECs. In this three-laser technique the pump and Stokes pulses are slightly detuned from transition frequencies, and a third strong hyperbolic-tangent laser pulse induces dynamic Stark shifts of the relevant transitions and compensates for third-order nonlinearities. If the timing of the three pulses is appropriately chosen, the nonlinear quantum system is prepared to almost complete population inversion between the two lower states in the Λ-like scheme. The paper shows that the efficiency of the nl-SCRAP is higher than the nonlinear stimulated Raman adiabatic passage (nl-STIRAP) technique, and this method can be used in one-photon as well as multi-photon transitions. The transfer process is robust concerning fluctuations of experimental parameters, such as peak Rabi frequencies, the time delay between pulses, and static detunings.

The synthesis of white-laser source based on the frequency conversion with the Stark-chirped rapid adiabatic passage

In this paper, an efficient cascaded sum frequency generation (SFG) model based on Stark-chirped rapid adiabatic passage is established, in which the laser of signal, intermediate, and output corresponds to three primary, and an approach of white laser source synthesis is proposed. The research results show that the energy of the red laser can be almost converted into blue laser, while the green laser intensity is extremely low in the cascade SFG process. The farther away from the optimal coupling delay parameters, the smaller the corresponding conversion efficiency is. Meanwhile, the pump intensity has a larger control range for conversion efficiency. On the basis of these findings, a white laser source with a color temperature of 6500 K can be synthesized. We first roughly adjust the pump intensity to reduce the conversion efficiency so that the red, green and blue lasers coexist at the output. Then, we fine-tune the coupling delay parameters so that the output power ratio meets 0.61:0.28:0.11. These research results can provide a theoretical basis for achieving efficient frequency conversion and the development of new optical devices.

Coupling modulation for efficient wavelength conversion with the Stark-chirped rapid adiabatic passage

We investigate the influence of nonlinear crystal’s coupling modulation on wavelength conversion based on Stark-chirped rapid adiabatic passage. The result shows that the distribution of the efficient conversion is zonal with the change of coupling delay parameter. In addition, the efficient wavelength conversion can be performed in counterintuitive and intuitive order, which can reduce the restriction on the condition of conversion process compared to the stimulated Raman adiabatic passage. When the width parameter d12 is fixed, the larger the width parameter d22 is, the higher the maximum conversion efficiency is and the larger the bandwidth for efficient wavelength conversion is. These findings provide a theoretical basis for the efficient acquisition of laser sources from the visible to the mid-infrared and to the ultraviolet.

Fractional population transfer among three-level systems in a cavity by Stark-shift-chirped rapid adiabatic passage

We show that the technique of Stark-chirped rapid adiabatic passage (SCRAP), hitherto used for complete population transfer among three states in atoms and molecules, offers a simple and robust method for creating coherent superpositions of states in the interaction of a three-level atom with cavity and laser fields. We also use this technique to generate maximally atom–photon entangled states. SCRAP in three-level systems uses three laser pulses: a strong far-off-resonant pulse modifies the transition frequencies by inducing dynamic Stark shifts and thereby creating time-dependent level crossings among the three diabatic states, while near-resonant and moderately strong pump and Stokes pulses, appropriately offset in time, drive the population between the initial and final states via adiabatic passage. In our method, the atom falls through a high-Q cavity and encounters the cavity mode and the laser beams such that the populations are transferred fractionally between two ground states (f-SCRAP). The populations of the created superposition are controlled by the detunings of the pump and cavity fields from the transition frequencies. Unlike the technique of fractional stimulated Raman adiabatic passage (f-STIRAP), f-SCRAP can be applied to one-photon as well as multiphoton transitions and it is a powerful alternative tool for f-STIRAP in the media exhibiting inhomogeneous broadening. This technique is robust against moderate variations in peak Rabi frequencies, in distance between the center of the cavity and axis of the pump and Stark laser beams and in the velocity of the atom.

Three-process cascaded frequency conversion based on Stark-chirped rapid adiabatic passage

In the field of nonlinear frequency conversion, the cascaded frequency conversion scheme is an effective means to obtain new wavelengths. In this paper, we demonstrate efficient frequency conversion through three cascaded three-wave mixing processes based on Stark-chirped rapid adiabatic passage, which are different from previous cascaded wavelength conversion processes based on stimulated Raman adiabatic passage. Further, by analyzing the relevant parameters in the three-process cascaded frequency conversion models we have established, we find that the new scheme increases the conversion range and has lower restrictions on the conversion conditions while maintaining extremely low intermediate frequency intensity. These advantages allow our work to be applied to the acquisition of a mid-infrared or visible laser.

Efficient cascaded wavelength conversion based on Stark-chirped rapid adiabatic passage

We demonstrate a highly efficient process of cascaded wavelength conversion among three states that is based on the Stark-chirped rapid adiabatic passage technique, and enables the achievement of nearly complete wavelength conversion in the mid-infrared laser generation process. By analyzing the relevant parameters in the model, we identify various factors that affect the efficiency of the conversion process. Compared with traditional cascaded wavelength conversion based on the technique of stimulated Raman adiabatic passage, the new conversion process not only maintains a high efficiency but also keeps the intermediate frequency strength low along the interacting length and achieves better stability when the relevant parameters change.

Deterministic implementations of quantum gates with circuit QEDs via Stark-chirped rapid adiabatic passages

We show that a set of universal quantum gates could be implemented robustly in a circuit QED system by using Stark-chirped rapid adiabatic passage (SCRAP) technique. Under the adiabatic limit we find that the population transfers could be deterministically passaged from one selected quantum states to the others, and thus the desired quantum gates can be implemented. The proposed SCRAP-based gates are insensitive to the details of the operations and thus relax the designs of the applied pulses, operational imperfections, and the decoherence of the system.

Stark-Chirped Rapid Adiabatic Passage in Presence of Dissipation for Quantum Computation

Stark-chirped rapid adiabatic passage (SCRAP) is an important technique used for coherent quantum controls. In this paper we investigate how the practically-existing dissipation of the system influences on the efficiency of the passage, and thus the fidelities of the SCRAP-based quantum gates. With flux-biased Josephson qubits as a specifical example, our results show clearly that the efficiency of the logic gates implemented by SCRAP are robust against the weak dissipation. The influence due to the non-adiabtic transitions between the adiabatic passages is comparatively significantly small. Therefore, the SCRAP-based logic gates should be feasible for the realistic physical systems with noises.

Quantum state engineering with flux-biased Josephson phase qubits by rapid adiabatic passages

In this article, the scheme of quantum computing based on the Stark-chirped rapid adiabatic passage (SCRAP) technique [L. F. Wei, J. R. Johansson, L. X. Cen, S. Ashhab, and F. Nori, Phys. Rev. Lett. 100, 113601 (2008)] is extensively applied to implement quantum state manipulations in flux-biased Josephson phase qubits. The broken-parity symmetries of bound states in flux-biased Josephson junctions are utilized to conveniently generate the desirable Stark shifts. Then, assisted by various transition pulses, universal quantum logic gates as well as arbitrary quantum state preparations can be implemented. Compared with the usual $\ensuremath{\pi}$-pulse operations widely used in experiments, the adiabatic population passages proposed here are insensitive to the details of the applied pulses and thus the desirable population transfers can be satisfyingly implemented. The experimental feasibility of the proposal is also discussed.

Stark-chirped rapid adiabatic passage among degenerate-level manifolds

We generalize Stark-chirped rapid adiabatic passage (SCRAP) to the case of two and three degenerate-level manifolds. The analysis of a degenerate-level system is facilitated by its subdivision into a set of smaller independently evolving subsystems corresponding to the minimal-sized invariant subspaces of the Hamiltonian. Population transfer from the starting to the final level is examined for different types of the invariant subspaces depending on the presence of dark states. It is shown that the complete transfer is feasible if the initial state is prepared into specific coherent superpositions. Our formalism is applicable to the general case of arbitrary numbers of degenerate states within each level and arbitrary couplings of the appropriate transitions. It represents a generalization of well-known Morris-Shore transformation to the case when the removed degeneracy of the sublevels leads to detuning from two-photon resonance. We give the application of the SCRAP formalism to the $^{87}\text{R}\text{b}$ atom.

Stark-Chirped Rapid Adiabatic Passage in a Multilevel Atom

We generalize Stark-chirped rapid adiabatic passage to the case of a multilevel atom. The atom is assumed to have two ground state levels g and f and an excited level e. The adiabatic passage is carried out by resonantly driving the g–e and f–e transitions with time-dependent pump and Stokes fields in the presence of strong far-off-resonant Stark field. Our formalism determines the states that participate in population transfer and is applicable to systems with arbitrary numbers of degenerate states in each level and arbitrary couplings of the g–e and f–e transitions. We give an application to adiabatic passage in Rb atom.

Stark-chirped rapid adiabatic passage among a three-state molecular system: Experimental and numerical investigations

We present extended experimental investigations and numerical studies on coherently driven population inversion in a three-state molecular quantum system by sequential double-Stark-chirped rapid adiabatic passage (SCRAP) (D-SCRAP) and three-state-SCRAP (T-SCRAP). D-SCRAP and T-SCRAP are alternative extensions of SCRAP. In D-SCRAP and T-SCRAP, a $\ensuremath{\Lambda}$-type quantum system is coherently driven by two laser pulses, the pump and Stokes pulses, which are slightly detuned from transition frequencies. A third strong laser pulse induces dynamic Stark shifts of the relevant transitions. If the timing of the three pulses is appropriately chosen, the quantum system is prepared to almost complete population inversion between the two lower states in the $\ensuremath{\Lambda}$-type level scheme. The transfer process is robust with regard to fluctuations of experimental parameters, provided some limitations are met. The paper presents convincing experimental data on D-SCRAP and T-SCRAP, driving efficient and selective population transfer to a highly excited vibrational level in nitrous oxide (NO) molecules. T-SCRAP yields transfer efficiencies of up to 95%. The efficiency of T-SCRAP is almost uneffected by the limited lifetime of the intermediate state in the $\ensuremath{\Lambda}$ system. The paper also presents data on the accurate experimental determination of Rabi frequencies and Stark shifts. This involves measurements of power broadening, Autler-Townes splittings, and Stark-shifted spectral lines in NO molecules. Moreover, we discuss the calibration of absolute transfer efficiences by comparison with stimulated emission pumping. The experimental data are confirmed by extended numerical simulations. The simulations also serve to intensively study the properties and dynamics of D-SCRAP and T-SCRAP.

Selective photodissociation in diatomic molecules by dynamical Stark-shift control

Selective population transfer in electronic states of dissociative molecular systems is illustrated by adopting a control scheme based on Stark-chirped rapid adiabatic passage (SCRAP). In contrast to the discrete N-level system, dynamical Stark shift is induced in a more complex manner in the molecular electronic states. Wavepacket dynamics on the light-induced potentials, which are determined by the detuning of the pump pulse, can be controlled by additional Stark pulse in the SCRAP scheme. Complete population transfer can be achieved by either lowering the energy barrier along the adiabatic passage or placing the initial wavepacket on a well-defined dressed state suitable for the control. The determination of the pulse sequence is sufficient for controlling population transfer to the target state.