<i>Ab initio</i>multimode linewidth theory for arbitrary inhomogeneous laser cavities

We present an ab-initio semi-analytical solution for the noise spectrum of complexcavity micro-structured lasers, including central Lorentzian peaks at the multimode lasing frequencies and additional sidepeaks due to relaxation-oscillation (RO) dynamics. In Ref. 1, we computed the central-peak linewidths by solving generalized laser rate equations, which we derived from the Maxwell-Bloch equations by invoking the fluctuation-dissipation theorem to relate the noise correlations to the steady-state lasing properties; Here, we generalize this approach and obtain the entire laser spectrum, focusing on the RO sidepeaks. Our formulation treats inhomogeneity, cavity openness, nonlinearity, and multimode effects accurately. We find a number of new effects, including new multimode RO sidepeaks and three generalized α factors. Last, we apply our formulas to compute the noise spectrum of single-and multimode photonic-crystal lasers.

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“…(7)] by comparing it with brute-force simulations of the generalized rate equations [Eq. (6)] and with previous theories [1,21] (Fig. 2).…”

Section: Validation and Main Predictions Of The Formulasupporting

confidence: 82%

“…where the parameters c µµ (x), γ(x), and a µ0 are obtained from SALT (as shown in Table 1) [1]. The nonlinear restoring force, c µµ (x), can be thought of as an effective gain rate (being proportional to the product of the lasing frequency ω µ and pump amplitude D 0 ).…”

Section: From Langevin Maxwell-bloch To the Oscillator Equationsmentioning

confidence: 99%

Ab initio theory of quantum fluctuations and relaxation oscillations in multimode lasers

2019

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“…We show here enhancements of ≈ 400, while higher values can easily be obtained; the enhancement is essentially not bounded in this computational model. However, in reality, it is bounded by quantum noise near threshold [93]. The side panels in the figure demonstrate that the LDOS peak scales quadratically with Q a near the EP [ Fig.…”

Section: F Giant Ldos Enhancement In Active Periodic Systemsmentioning

confidence: 99%

General theory of spontaneous emission near exceptional points

Pick¹,

Zhen²,

et al. 2017

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Abstract:We present a general theory of spontaneous emission at exceptional points (EPs)-exotic degeneracies in non-Hermitian systems. Our theory extends beyond spontaneous emission to any light-matter interaction described by the local density of states (e.g., absorption, thermal emission, and nonlinear frequency conversion). Whereas traditional spontaneous-emission theories imply infinite enhancement factors at EPs, we derive finite bounds on the enhancement, proving maximum enhancement of 4 in passive systems with second-order EPs and significantly larger enhancements (exceeding 400×) in gain-aided and higher-order EP systems. In contrast to non-degenerate resonances, which are typically associated with Lorentzian emission curves in systems with low losses, EPs are associated with non-Lorentzian lineshapes, leading to enhancements that scale nonlinearly with the resonance quality factor. Our theory can be applied to dispersive media, with proper normalization of the resonant modes. References and links1. E. M. Purcell, "Spontaneous emission probabilities at radio frequencies," Phys. Rev. 69, 681--681 (1946). (CRC Press, 1995, vol. X). 3. S. V. Gaponenko, Introduction to Nanophotonics (Cambridge University, 2010 H. Yokoyama and K. Ujihara, Spontaneous Emission and Laser Oscillation in Microcavities

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“…Nevertheless, one can imagine a treatment where one calculates the response of a structure to a pump at a given frequency, and then determine the effect of pump frequency fluctuation by a perturbation approach. 14,40,42,53 At the final stage of the revision, it was brought to our attention that concurrent to our work, there is another proposal for performing first-principles simulations of the SBS process using a transformation optics approach. 54 Both our work and the work in Ref.…”

Section: Discussion and Summarymentioning

confidence: 96%

Invited Article: Acousto-optic finite-difference frequency-domain algorithm for first-principles simulations of on-chip acousto-optic devices

2017

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We introduce a finite-difference frequency-domain algorithm for coupled acousto-optic simulations. First-principles acousto-optic simulation in time domain has been challenging due to the fact that the acoustic and optical frequencies differ by many orders of magnitude. We bypass this difficulty by formulating the interactions between the optical and acoustic waves rigorously as a system of coupled nonlinear equations in frequency domain. This approach is particularly suited for on-chip devices that are based on a variety of acousto-optic interactions such as the stimulated Brillouin scattering. We validate our algorithm by simulating a stimulated Brillouin scattering process in a suspended waveguide structure and find excellent agreement with coupled-mode theory. We further provide an example of a simulation for a compact on-chip resonator device that greatly enhances the effect of stimulated Brillouin scattering. Our algorithm should facilitate the design of nanophotonic on-chip devices for the harnessing of photon-phonon interactions.

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Ab initiomultimode linewidth theory for arbitrary inhomogeneous laser cavities

Cited by 36 publications

References 88 publications

Ab initio theory of quantum fluctuations and relaxation oscillations in multimode lasers

Ab initio theory of quantum fluctuations and relaxation oscillations in multimode lasers

General theory of spontaneous emission near exceptional points

Invited Article: Acousto-optic finite-difference frequency-domain algorithm for first-principles simulations of on-chip acousto-optic devices

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