We conduct a photon transport analysis on a deterministic photon subtractor utilizing single-photon Raman interaction with a three-level Λ-type atom inside a waveguide-coupled bimodal cavity. By incorporating parameters from an existing experimental cavity QED platform, we demonstrate that the photon subtractor can achieve success probabilities approaching unity. In the second part, we demonstrate a potential application of deterministic photon subtraction for generating non-classical light, specifically enabling the creation of multi-photon Fock states that can be utilized in quantum metrology at the Heisenberg limit. The results highlight the potential of deterministic photon subtraction for advancing the development of high-efficiency non-classical light sources.
We conduct a photon transport analysis on a deterministic photon subtractor utilizing single-photon Raman interaction with a three-level Λ-type atom inside a waveguide-coupled bimodal cavity. By incorporating parameters from an existing experimental cavity QED platform, we demonstrate that the photon subtractor can achieve success probabilities approaching unity. In the second part, we demonstrate a potential application of deterministic photon subtraction for generating non-classical light, specifically enabling the creation of multi-photon Fock states that can be utilized in quantum metrology at the Heisenberg limit. The results highlight the potential of deterministic photon subtraction for advancing the development of high-efficiency non-classical light sources.
The single-photon Raman interaction has emerged as a promising tool for deterministic photon subtraction, acting as a photon-activated switch in which the first arriving photon renders the system transparent to subsequent photons. Here, we employ the input-output formalism to perform a single-photon transport analysis within a photon subtractor consisting of a three-level quantum emitter coupled to a bimodal cavity-waveguide system. The analysis provides the frequency response of the system and reveals how it is affected by the key physical parameters of the cavity modes, such as coupling strengths and decay rates. We utilize these results to calculate the probability of successful photon subtraction from pulses of different temporal shapes, durations, and carrier frequencies. Subsequent analysis combines the input-output formalism with the quantum trajectory method to numerically verify the analytical findings as well as to assess the impact of photon number of the input pulse on the subtractor's performance. Our findings highlight the single-photon model's capability in predicting the system's response to multiphoton inputs in the pulsed regime as well as its potential utility in the design of efficient single-photon subtractors.
Abstract This work presents a deterministic photon subtraction scheme that selectively extracts photons from an input light stream based on their arrival time sequence. The scheme exploits the temporal entanglement generated during single‐photon Raman interaction in a chiral waveguide coupled to a cascade of Λ‐type atoms. It is demonstrated that this photon subtractor enables the generation of high‐fidelity and modal purity multi‐photon Fock states. Using a variational approach, the modal structure of the output light is identified, based on a non‐orthogonal basis formed through post‐selection of the output pulses. Within an input‐output network framework, numerical simulations are performed to calculate the quantum state of the output light. Additionally, the use of the generated Fock‐state pulses in optical interferometry is investigated, demonstrating their potential for quantum metrology applications at the Heisenberg limit.
Abstract We propose a scheme for deterministic single photon subtraction based on Single Photon Raman Interaction (SPRINT) with a three-level quantum emitter coupled to a chiral waveguide and present an analytical and numerical study of its feasibility. We show that single photon subtraction probability for pulsed input light in a coherent or a Fock state can approach unity in the ideal limit and discuss the potential of various reported quantum emitter-waveguide platforms as candidates for experimental realization of our scheme. The use of chiral slow-light photonic crystal waveguides coupled to Λ -type emitters can perform efficient photon subtraction. While integrating cold atoms to such systems remains technically challenging, solid-state emitters offer a potentially practical path to realize such photon subtraction.
Abstract We explore a recently demonstrated deterministic photon subtraction scheme, based on single-photon Raman interaction with a Λ-type three-level atom, as a tool for manipulating quantum state of few-photon light pulses. We establish a comprehensive theoretical framework using input–output formalism and quantum regression theorem, enabling calculation of the first order autocorrelation matrices of the output light and identification of the temporal modes present in the generated light via their eigendecomposition. By modeling the entire system as a quantum network consisting multiple virtual cavities and a lambda-type emitter cascaded in two parallel guided modes of opposite propagation directions, we extract the quantum state occupying the modes of interest. For both squeezed vacuum and coherent light input pulses, the Wigner function of the output light after photon subtraction clearly reveals its non-Gaussian character. Furthermore, we propose a measurement-based scheme on the subtracted photon which can lead to conditional generation of quantum states resembling Schrodinger’s kitten state directly from coherent input light with fidelities above 99%. This result is particularly nothworthy, as coherent pulses, unlike the squeezed vacuum inputs commonly used in previous studies, are readily available in most experimental setups.
Photon subtraction and addition are essential non-Gaussian processes in quantum optics, where conventional methods using linear optics and number-resolving detection often suffer from low success probability. Here, we introduce the concept of \textit{dynamic stimulated emission}, whereby a quantum emitter undergoes stimulated emission with a time-dependent coupling. Despite interacting with a multimode photon field, we show that, for both two- and three-level emitters, their dynamics can mimic that of a single-mode Jaynes-Cummings model. This feature can be used to deterministically add or subtract a photon while maintaining a single propagating optical mode. We provide semi-analytic solutions to this problem for Fock states, enabling deterministic and unconditional photon addition and subtraction with fidelity F>0.996. Our semi-analytic solutions are provided for both dynamically coupled two-level systems and for three-level systems whose dynamical coupling is controlled by a coherent laser drive. Moving beyond individual Fock states, we further showcase the ability to subtract and add single photons to photon-number superposition states. We show that Schr{ö}dinger cat states can be prepared from squeezed vacuum input via cascaded subtraction or cascaded addition. Finally, we show that our photon-addition process can be used to add a photon to any squeezed and displaced state with high success probability and fidelity F>0.99, thereby potentially converting quantum emitters from single-photon sources to sources of single-photon-added Gaussian states without the need for inline squeezing. Our protocols provide a path towards integrating quantum emitters to construct efficient sources of single-mode non-Gaussian light beyond single photons.
The ability to control light at the single photon level is essential for fully harnessing the power of quantum information theory, and precision measurements. In this thesis, we study two phenomena which can help us to create, and shape light at the smallest scale. In the first part of the thesis, we explore deterministic single photon subtraction based upon single photon Raman interaction of a single three-level Λ-type quantum emitter in a bi-modal cavity or coupled with a chiral waveguide. We study the effect of photon subtraction from different types of optical inputs –- continuous-wave or pulsed coherent states and Fock states, and dependence of the fidelity of subtraction upon key system parameters. We also discuss the suitability and prospects of using different emitter-waveguide systems reported in literature to successfully extract a single photon from an optical input. We find that a quantum dot coupled with a photonic crystal waveguide with high group index could subtract photons with fidelity close to unity. Moreover, we explore how such a SPRINT-based single photon subtraction process can be used to create non-Gaussian states with negative values of Wigner distribution, and negative conditional entropies. Such states can be used as quantum resources in various fields of quantum information theory. Finally, as an interesting example, we also discuss how this mechanism can also be used to create non-classical Fock states of arbitrary photon number. \nIn the second part of this thesis, we study how to shape the emission from a single solid-state quantum emitter, in particular an NV⁻ center in diamond, using two dimensional patterns with sub-wavelength features. We propose a pattern etched on the surface of a diamond sample that enhances the NV's emission in a particular direction, and maximizes coupling with a waveguide substantially far away from the diamond-air interface. Our proposed structure was designed using the adjoint optimization technique, which significantly reduces the amount of computational resources compared to brute-force methods to design an optical element with desired properties. Our structure exhibits a higher directionality of emission compared to other nanophotonic structures reported in the literature -- solid immersion lenses, nanopillars, and bull's eye structures. Finally, we also discuss in details the steps pertaining to setting up a confocal microscope in our laboratory for imaging NV centers, and characterizing our proposed device.