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Multimode optomechanics exhibiting several intriguing phenomena, such as coherent wavelength conversion, optomechanical synchronization, and mechanical entanglements, has garnered considerable research interest for realizing a new generation of information processing devices and exploring macroscopic quantum effect. In this study, we proposed and designed a hetero-optomechanical crystal (OMC) zipper cavity comprising double OMC nanobeams as a versatile platform for multimode optomechanics. Herein, the heterostructure and breathing modes with high mechanical frequency ensured the operation of the zipper cavity at the deep-sideband-resolved regime and the mechanical coherence. Consequently, the mechanical breathing mode at 5.741 GHz and optical odd mode with an intrinsic optical Q factor of 3.93 × 105 were experimentally demonstrated with an optomechanical coupling rate g0 = 0.73 MHz between them, which is comparable to state-of-the-art properties of the reported OMC. In addition, the hetero-zipper cavity structure exhibited adequate degrees of freedom for designing multiple mechanical and optical modes. Thus, the proposed cavity will provide a playground for studying multimode optomechanics in both the classical and quantum regimes.

Photonic Ising machine is a new paradigm of optical computing, which is based on the characteristics of light wave propagation, parallel processing and low loss transmission. Thus, the process of solving the combinatorial optimization problems can be accelerated through photonic/optoelectronic devices. In this work, we have proposed and demonstrated the so-called Phase-Encoding and Intensity Detection Ising Annealer (PEIDIA) to solve arbitrary Ising problems on demand. The PEIDIA is based on the simulated annealing algorithm and requires only one step of optical linear transformation with simplified Hamiltonian calculation. With PEIDIA, the Ising spins are encoded on the phase term of the optical field and only intensity detection is required during the solving process. As a proof of principle, several 20-dimensional Ising problems have been solved with high ground state probability (0.98 within 1000 iterations for the antiferromagnetic cubic model, > 0.99 within 4000 iterations for two random spin-glass models, respectively).

Based on a phase-modulated metallic nanoslit array, an angular momentum (AM) beam splitter has been demonstrated to distinguish both spin and orbital components carried by the light beam. With such a device, the AM modes could be coupled into nondiffracting surface plasmonic beams propagating toward different directions. According to the experimental results, the extinction ratio for spin AM beam splitting is larger than 10 and the spatial interval of adjacent orbital AM modes (with a topological charge interval of 2) is more than 1.1 μm. We believe that such a device would have great potential to achieve a highly compact photonic integrated circuit with the plasmonic beam.

In quantum optics, orbital angular momentum (OAM) is very promising to achieve high-dimensional quantum states due to the nature of infinite and discrete eigenvalues, which is quantized by the topological charge of l. Here, a heralded single-photon source with switchable OAM modes is proposed and demonstrated on silicon chip. At room-temperature, the heralded single photons with 11 OAM modes (l=2~6, -6~-1) have been successfully generated and switched through thermo-optical effect. We believe that such an integrated quantum source with multiple OAM modes and operating at room-temperature would provide a practical platform for high-dimensional quantum information processing. Moreover, our proposed architecture can also be extended to other material systems to further improve the performance of OAM quantum source.

Photon-pair sources are the key devices for quantum photonic applications; most of them are optically pumped. Here we present our design of an electrically injected photon-pair source based a Bragg-reflection-waveguide (BRW) GaInP/AlGaInP quantum well laser and internal spontaneous parametric down conversion, targeting at the wavelengths near 1.3 μm for signal and idler photons. We establish a model that allows us to simulate the major characteristics of the device. Our work shows the feasibility to extend the demonstration of the electrically injected BRW photon-pair source at 1.57 μm [Boitier et al. , “Electrically injected photon-pair source at room temperature,” Physical Review Letters , vol. 112, no. 18, 2014, Art. no. 183901] to another technologically interested wavelength.

The orbital angular momentum (OAM) carried by photons defines an infinitely dimensional discrete Hilbert space. With OAM modes, high-dimensional quantum states can be achieved for quantum communication and cryptography. Here we demonstrate a heralded single-photon source with a switchable OAM mode, which consists of a heralded single-photon source and an integrated OAM emitter as the mode converter. As the first step, the heralded single-photon source is based on the dispersion-shifted fiber. In this work, the OAM mode (quantized by topological charge l ) carried by the heralded single photon (at fixed wavelength of 1555.75 nm) can be switched within the range of l = 3 – 7 while the mode purity is more than 80%.

Two properly designed columns of orthogonally tilted and spatially varied nano-apertures have been demonstrated to achieve polarization-controlled launching of the localized cosine-Gauss beam, which is a kind of highly localized surface plasmonic wave without diffraction. According to the experimental results, the generated unidirectional propagating plasmonic beam could propagate with a non-diffracting length of up to 57μm as well as the extinction ratio of more than 150. We believe that our proposed device would play an important role in highly compact photonic circuit on-chip with plasmonic wave.

Lasers differ from other light sources in that they are coherent, and their coherence makes them indispensable to both fundamental research and practical application. In optomechanical cavities, phonon and photon lasing is facilitated by the ability of photons and phonons to interact intensively and excite one another coherently. The lasing linewidths of both phonons and photons are critical for practical application. However, thus far, these linewidths have not been explored in detail in cavity optomechanical systems. This study investigates the underlying dynamics of lasing in optomechanical cavities and experimentally demonstrates simultaneous photon and phonon lasing with narrow linewidths in a silicon optomechanical crystal cavity. We find that the linewidths can be accounted for by two distinct physical mechanisms in two regimes, namely the normal regime and the reversed regime, where the intrinsic optical decay rate is either larger or smaller than the intrinsic mechanical decay rate. In the normal regime, an ultra-narrow spectral linewidth of 5.4 kHz for phonon lasing at 6.22 GHz can be achieved regardless of the linewidth of the pump light, while these results are counterintuitively unattainable for photon lasing in the reversed regime. These results pave the way towards harnessing the coherence of both photons and phonons in silicon photonic devices and reshaping their spectra, potentially opening up new technologies in sensing, metrology, spectroscopy, and signal processing, as well as in applications requiring sources that offer an ultra-high degree of coherence., 20 pages, 4 figures

Micro- and nanomechanical resonators have emerged as promising platforms for sensing a broad range of physical properties, such as mass, force, torque, magnetic field, and acceleration. The sensing performance relies critically on the motional mass, mechanical frequency, and linewidth of the mechanical resonator. Herein, we demonstrate a hetero optomechanical crystal (OMC) cavity based on a silicon nanobeam structure. The cavity supports phonon lasing in a fundamental mechanical mode with a frequency of 5.91 GHz, an effective mass of 116 fg, and a mechanical linewidth narrowing in the range from 3.3 MHz to 5.2 kHz, while the optomechanical coupling rate is as high as 1.9 MHz. With this phonon laser, on-chip sensing can be predicted with a resolution of δ λ / λ = 1.0 × 10 − 8 . The use of a silicon-based hetero OMC cavity that harnesses phonon lasing could pave the way toward high-precision sensors that allow silicon monolithic integration and offer unprecedented sensitivity for a broad range of physical sensing applications.

This paper summarizes our research work on optoelectronic devices with nanostructures. It was indicated that by manipulating so called “general energy-bands” of fundamental particles or quasi-particles, such as photon, phonon, and surface plasmon polariton (SPP), novel optoelectronic characteristics can be obtained, which results in a series of new functional devices. A silicon based optical switch with an extremely broadband of 24 nm and an ultra-compact (8 mm × 17.6 mm) footprint was demonstrated with a photonic crystal slow light waveguides. By proposing a nanobeam based hetero optomechanical crystal, a high phonon frequency of 5.66 GHz was realized experimentally. Also, we observed and verified a novel effect of two-surface-plasmon-absorption (TSPA), and realized diffraction-limit-overcoming photolithography with resolution of ~1/11 of the exposure wavelength.

A coupling structure with a shape of isosceles trapezoid is experimentally demonstrated for injecting lightwave into silicon slot waveguide operating at 1064 nm. A transfer waveguide is adopted to mimic a silicon emitter and the coupling losses of varied mode sizes of incident lightwave are measured. According to experimental results, the low coupling loss region of “

Smith–Purcell radiation (SPR) is the electromagnetic wave generated by free electrons passing above a diffraction grating, and it has played an important role in free-electron light sources and particle accelerators. Orbital angular momentum (OAM) is a new degree of freedom that can significantly promote the capacity of information carried by an electro-magnetic beam. In this paper, we propose an integrable method for generating vortex Smith–Purcell radiation (VSPR), namely, SPR carrying OAM, by having free-electron bunches pass on planar holographic gratings. VSPRs generated by different electron energies, with different topological charges of the OAM, radiation angles, and frequencies are demonstrated numerically. It is also found that, for high-order radiation, the topological charge of the OAM wave will be multiplied by the radiation order. This work introduces a new way to generate SPR with OAM and provides a method to achieve an integratable and tunable free-electron OAM wave source at different frequency regions.

It is tough work to measure the orbital angular momentum (OAM) spectrum due to the requirement of a reference light or photodetector arrays, while measuring the spin angular momentum (SAM) is readily convenient and matured. In this work, the so-called OAM–SAM nonseparable states are employed, and the OAM spectrum can be obtained only by measuring the Stokes parameters of an arbitrary light beam with low loss noncascading structure and a single point detector. According to the experimental results, the fidelity of the measured OAM spectrum can be as high as 95.2% and 94.3% for OAM eigenstates and superposed states, respectively.

We present our design of an electrically-driven device based on a GaInP/AlGalnP quantum well and a Bragg-reflection waveguide to generate photon pairs near 1.3-micrometer wavelengths through internal spontaneous parametric down-conversion.

In this paper we study slot structures in the 120° photonic crystal waveguide (PCW) bends. We find that the transmission characteristics of the slotted PCW bend can be simply predicted by analyzing the corresponding straight PCW. According to our mode analysis for straight PCW, the slot structure blue shifts the stopband of the fundamental mode, while enhances the light confinement at slot side. The experiment shows good agreements with the simulation. Furthermore, a low bending loss in broad bandwidth has been obtained in the capsule-shaped slot PCW bend, which is very useful for broadband application.

The axis tilt of light beam in optical system would introduce the dispersion of orbital angular momentum (OAM) spectrum. To deal with it, a two-step method is proposed and demonstrated. First, the tilt angle of optical axis is identified with a deduced relation between the tilt angle and the variation of OAM topological charges with different reference axes, which is obtained with the help of a charge coupled device (CCD) camera. In our experiments, the precision of measured tilt angle is about 10−4rad with topological charges of −3~3. With the measured angle value, the additional phase delay due to axis tilt can be calculated so that the dispersion of OAM spectrum can be corrected with a simple formula while the optical axis is not aligned. The experimental results indicate that the original OAM spectrum has been successfully extracted for not only the pure state but also the superposed OAM states.

Radially polarized orbital angular momentum (OAM) beams could be applied in optical manipulation and optical microscopy. An integrated OAM beam emitter with radially polarized radiation is proposed on shallow-ridge silicon microring with azimuthally distributed gratings etched on top of the ring waveguide. Two key structural parameters, the number of grating elements, and the dimension of each grating element are optimized by considering both the OAM order purity $(C_{p})$ and the total radiation efficiency $(\eta_{all})$ . With elaborate design, $C_{p} = \,\sim\!98\%$ , $ \eta_{all} =\, \sim\!49\%$ are achieved by simulations, and the calculated energy ratio between the far-field radially and azimuthally polarized component is more than 11 dB, which indicates that the radially polarized component is predominant in the radiated electromagnetic field.

As a fundamental tool for light-matter interactions, plasmonic vortex (PV) is extremely useful due to the unique near field property. However, it is a pity that, up to now, the orbital angular momentum (OAM) carried by PVs could not be dynamically and continuously tuned in practice as well as the properties of fractional PVs are still not well investigated. By comparing with two previously reported methods, it is suggested that our proposal of utilizing the propagation induced radial phase gradient of incident Laguerre-Gaussian (LG) beam is a promising candidate to sculpture PVs from integer to fractional OAM dynamically. Consequently, the preset OAM of PVs could have four composing parts: the incident spin and orbital angular momentum, the geometric contribution of chiral plasmonic structure, and the radial phase gradient dependent contribution. Moreover, an analytical expression for the fractional PV is derived as a linear superposition of infinite numbers of integer PVs described by Bessel function of the first kind. It is also shown that the actual mean OAM of a fractional PV would deviate from the preset value, which is similar with previous results for spatial fractional optical vortices.

The frequency range that surface plasmon polariton (SPP) mode exists is mainly limited by the metal material. With high permittivity dielectrics above metal surface, the SPP mode at high frequency has extremely large loss or can be cutoff, which limits the potential applications of SPP in the field of optical interconnection, active SPP devices and so on. To extend the frequency range of SPP mode, the surface mode guided by metal/dielectric multilayers meta-material has been studied based on the theory of electromagnetic field. It is demonstrated that surface mode not only could be supported by the meta-material but also extends the frequency to where conventional metal SPP cannot exist. Meanwhile, the characteristics of this surface mode, such as dispersion relation, frequency range, propagation loss and skin depth in meta-material and dielectrics, are also studied. It is indicated that, by varying the structure parameters, the meta-material guided SPP mode presents its advantages and flexibility over traditional metal one.

Optomechanical crystals are combinations of photonic and phononic crystals, which simultaneously control optical and acoustic waves with nanoscale periodic structure and form optomechanical systems with high mechanical frequency and lager photon-phonon interaction.

A series of plasmonic devices are proposed to generate multipatterned and two-dimensional optical lattices with or without helicity. Both the spin and orbital angular momentum of incident beam together with the excited polygonal plasmonic mode contribute to the formation of optical lattices due to the spin-orbit coupling. The impact of the mode property of incident beams on lattice pattern deforming is also discussed. Due to the compactness and flexible tunability, we believe that this work would facilitate the utilization of optical lattices in various on-chip applications.

Optomechanical crystal is a combination of both photonic and phononic crystal. It simultaneously confines light and mechanical motion and results in strong photon-phonon interaction, which provides a new approach to deplete phonons and realize on-chip quantum ground state. It is promising for both fundamental science and technological applications, such as mesoscopic quantum mechanics, sensing, transducing, and so on. Here high optomechanical coupling rate and efficiency are crucial, which dependents on the optical-mechanical mode-overlap and the mechanical frequency (phonon frequency), respectively. However, in the conventional optomechanical-crystal based on the same periodical structure, it is very difficult to obtain large optical-mechanical mode-overlap and high phonon frequency simultaneously. We proposed and demonstrated nanobeam cavities based on hetero optomechanical crystals with two types of periodic structure. The optical and mechanical modes can be separately confined by two types of periodic structures. Due to the design flexibility in the hetero structure, the optical field and the strain field can be designed to be concentrated inside the optomechanical cavities and resemble each other with an enhanced overlap, as well as high phonon frequency. A high optomechanical coupling rate of 1.3 MHz and a high phonon frequency of 5.9 GHz are predicted theoretically. The proposed cavities are fabricated as cantilevers on silicon-on-insulator chips. The measurement results indicate that a mechanical frequency as high as 5.66 GHz is obtained in ambient environment, which is the highest frequency demonstrated in one-dimensional optomechanical crystal structure.

Nanostructure is an effective solution for realizing optoelectronic devices with compact size and high performances simultaneously. This paper reports our research progress on integrated nanophotonic devices for optical interconnections. We proposed a parent-sub micro ring structure for optical add-drop multiplexer (OADM) with compact footprint, large free spectral range, and uniform channel spacing. All eight channels can be multiplexed and de-multiplexed with 2.6 dB drop loss, 0.36 nm bandwidth (>40 GHz), -20 dB channel crosstalk, and high thermal tuning efficiency of 0.15 nm/mW. A novel principle of optical switch was proposed and demonstrated based on the coupling of the defect modes in photonic crystal waveguide. Switching functionality with bandwidth up to 24 nm and extinction ratio in excess of 15 dB over the entire bandwidth was achieved, while the footprint was only 8 μm×17.6 μm. We proposed an optical orbital angular momentum (OAM) coding and decoding method to increase the data-carrying capacity of wireless optical interconnect. An integrated OAM emitter, where the topological charge can be continuously varied from -4 to 4 was realized. Also we studied ultrafast modulated nLED as the integrated light source for optical interconnections using a nanobeam cavity with stagger holes.

Due to the nature of infinite dimensionality, the orbital angular momentum (OAM) has been considered as a new degree of freedom of light and widely expanded the scopes of substantial optical applications such as optical telecommunication, quantum information, particle manipulation and imaging. In recent years, the integrated photonic OAM emitters have been actively investigated due to both compactness and tunability. Essentially, the number of available OAM modes by dynamic switching should be large enough so that the dimensionality of OAM could be explored as much as possible. In this work, an integrated photonic emitter with a wide switching range of OAM modes is theoretically developed, numerically simulated and experimentally verified. The independence of the micro-ring cavity and the scattering unit provides the flexibility to design the device and optimize the performance. Specifically, the dynamic switching of nine OAM modes (l = −4 ~ 4) with azimuthal polarization has been demonstrated by electrically controlled thermo-optic effect.

Surface plasmon amplification by stimulated emission of radiation (SPASER) is discovered and used for realizing lasers at nanometer scale. The conventional gain media that are applied in SPASER are solid materials, such as organic dye or semiconductor, which limits the frequency range of SPASER. The free electrons could be considered as a kind of gain medium for emitting radiation. Here, we investigate theoretically the SPASER, which is excited by free electrons. We also demonstrate the tunable, deep-ultraviolet, and ultracompact laser numerically by having free electrons interact with surface plasmon polariton mode supported on metal surface. The output power density could reach about 30 W/μm2 and the wavelength in deep ultraviolet could be widely tuned by varying the electron energy. This work offers a way of realizing integrated free electron laser in the ultraviolet frequency region.

Optical gain spectra of InGaAsP MQW for photonic crystal waveguide (PCWG) were simulated by the method with considering the variation of group velocity and the natural broadening synthetically. The dependence of the first mode's gain maximum on the width of PCWG was discussed. To improve the mode characteristics and the gain performances in the 2-D PCWG with relative large width, we proposed a new structure by combining a microcavity inside the 2-D PCWG. Mode characteristics in proposed structure were analyzed and the transmission performance was simulated by the FDTD method. The simulation results show that improved longitudinal mode characteristics can be obtained even in the W3 PCWG with relative wide waveguide width because of the additional frequency selecting mechanism provided by the microcavity.

Two-dimensional (2D) slab photonic crystal waveguides (PCWGs) on silicon-on-insulator (SOI) wafer were designed and fabricated. Full photonic band gap, band gap guided mode, and index guided mode were observed by measuring the transmission spectra. Mini-stop-bands in the PCWG were simulated with different structure parameters. Coupling characteristics of PCWG were investigated theoretically considering the imperfections during the fabrication process. It was found that suppressing power reservation effect can realize both short coupling length and high coupling efficiency.

An integrated device, which consists of a variable amplitude splitter and an orbital angular momentum (OAM) emitter, is proposed for the superposition of optical vortex beams. With fixed wavelength and power of incident beam, the OAM of the radiated optical superimposed vortex beam can be dynamically tuned. To verify the operating principle, the proposed device has been fabricated on the SOI substrate and experimentally measured. The experimental results confirm the tunability of superimposed vortex beams. Moreover, the ability of independently varying the OAM flux and the geometric distribution of intensity is illustrated and discussed with numerical simulation. We believe that this work would be promising in various applications.

A “cobweb” structure is demonstrated to serve as the gratings for the emission of optical vortices, based on a microring cavity. The scattered optical vortices with topological charges of −4 ∼ 4 were experimentally obtained.

A split-nanobeam optomechanical crystal cavity is proposed. By adjusting the split width, an ultra-small effective motion mass as small as 5.2fg is realized with a high mechanical frequency of 7.55GHz.

The relative phase shift among different components in the superposition of orbital angular momentum (OAM) states contains significant information. However, with existing methods of measuring the OAM spectrum, the phase term of the spectrum coefficient is hard to obtain. In this Letter, a mode-matching method is proposed to identify the complex OAM spectrum with a Mach-Zehnder interferometer and a charge-coupled device camera. It has the potential to extend the applications of OAM in scenarios sensitive to the phase factor, for instance, in imaging and quantum manipulation. The method is experimentally demonstrated with the superposition of two or three OAM states, while the maximum deviation of the energy ratio and the relative phase shift is 8.4% and 5.5% of 2π, respectively.

Photonic crystals have drawn a lot of attention due to their potential in guiding, controlling, and manipulating photons. This paper reports our recent research on the functional devices based on photonic crystal waveguides (PCWs).

An optomechanical crystal nanobeam cavity with high optomechanical coupling rate is proposed and fabricated. Only by adjusting the radius of the air holes, the cavity realizes an optomechanical coupling rate as high as 1.24 MHz.

In this work, an explicit formula is deduced for identifying the orbital angular moment (OAM) of vectorial vortex with space-variant state of polarization (SOP). Different to scalar vortex, the OAM of vectorial vortex can be attributed to two parts: the azimuthal gradient of Pancharatnam phase and the product of the azimuthal gradient of orientation angle of SOP and relevant solid angle on the Poincar\'{e} sphere. With our formula, a geometrical description for OAM of light beams can be achieved under the framework of the traditional Poincar\'{e} sphere. Numerical simulations for two types of vectorial vortices have been carried on to confirm our presented formula and demonstrate the geometrical description of OAM. Furthermore, the finding will pave the way for precise characterization of OAM charge of vectorial vortices., Comment: 10 pages, 5 figures

A photonic crystal nanobeam cavity with stagger-holes in InP/InGaAsP heterostructure is proposed for ultrafast direct modulation. The modulation bandwidth for the proposed nano-light-emitting-diode could be over 60 GHz with optimal Q (2150) and V eff (2.3(λ 0/2n)3).

Plasmonic enhancement of spontaneous emission with a nanostrip metallic waveguide is evaluated. Purcell factor increases dramatically with narrowing strip width while enhancement of the waveguide offers strong tolerance to wide-linewidth emitters.

Through weighted multi-beam interference in silicon waveguides, identifying the topology charge of optical angular momentum (OAM) beams is experimentally demonstrated. Based on this approach, an OAM receiver can be obtained for detecting and decoding.

Two dimensional slab photonic crystal waveguides were designed and fabricated. Full photonic band gap, band gap guided mode, and mini-stop-bands were observed. Passive and active performances were investigated theoretically and experimentally.

Mode selection mechanism is induced to W3 photonic crystal waveguide by combining a microcavity structure inside the waveguide. Modified mode characteristics are analyzed by photonic energy band and FDTD simulation.

Coupling characteristics and gain performances of slab photonic crystal waveguides were investigated theoretically. The simulation results are reported in this paper.

In this paper, we investigate the structure parameters dependence of central frequency as well as bandwidth of mini stop-bands in two-dimensional photonic crystal waveguides.

Optical gain spectra of InGaAsP MQW with different PCWG were simulated by considering the variation of group velocity and the natural broadening synthetically. An optimal width of the PCWG was demonstrated for maximum gain enhancement theoretically.

In this paper, we propose a fluid sensor based on transmission dip caused by mini stop-band in 2D photonic crystal waveguides. Simulation results shows that it has large detective range and relative high sensitivity.

An optomechanical crystal nanobeam cavity, only by increasing the radius of air holes in the defect region, is proposed and optimized for a high optomechanical coupling rate. In our proposed cavity, the photonic and phononic defect modes are simultaneously confined by each corresponding bandgap, and the overlap of the optical and mechanical modes can be improved simply by adjusting the radius of the air holes. Accordingly, an optomechanical coupling rate (g) as high as 1.16 MHz is obtained, which is the highest coupling rate among the reported optomechanical crystal cavities. What’s more, the proposed cavity also exhibits a high mechanical frequency of 4.01 GHz and a small effective mass of 85 fg for the fundamental mechanical mode.

Purcell factor of a nanostrip plasmon waveguide is evaluated via a full integration form of Fermi's golden rule and power dissipation spectrum. Purcell factor is dramatically increased with narrower strip width, corresponding to the tight confinement in the ultrasmall gap region. Furthermore, inclusion of energy distribution among useful and lossy modes would reduce the Purcell factor severely, yet the enhancement range could be broadened and the tolerance of emission linewidth strengthened. Although the dissipation issue remains serious near the resonant frequency, it is shown that wide-linewidth emitters in the off-resonance region could also be effectively enhanced with nanostrip waveguide, suggesting a promising path to practical integrated emitters.

A simple on-chip integrated structure is proposed to generate optical orbital angular momentum (OAM) beams, where only silicon waveguides and couplers are involved. The operating principle is based on mode converting and proper controlling the phase shift of second-order propagating mode so that OAM modes with charge numbers of 1 or -1 can be selectively generated with mode purity > 90%. The proposed device is very compact with footprint of

The Purcell factor (PF) of the propagating surface plasmon polariton (SPP) mode on metallic grating is evaluated with full integration formula of Fermi's golden rule, while both spontaneous emission linewidth of single quantum dot and the spectrum broadening of photonic density of state (DOS) due to the propagation loss of SPP mode are involved. It is found that the PF would be degraded by taking account of the emission linewidth. For emitters with narrow linewidth, the DOS broadening is dominant while it would be helpful to some degree for wide-linewidth emitters.