We investigate the nonlinear optical response of suspended one-dimensional (1D) photonic crystal nanocavities fabricated on a silicon nitride chip. Strong thermo-optical nonlinearities are demonstrated for input powers as low as $2\mu \text{W}$ and a self-sustained pulsing regime is shown to emerge with periodicity of several seconds. As the input power and laser wavelength are varied the temporal patterns change in period, duty cycle, and shape. This dynamics is attributed to the multiple timescale competition between thermo-optical and thermo-optomechanical effects and closely resembles the relaxation oscillations states found in mathematical models of neuronal activity. We introduce a simplified model that reproduces all the experimental observations and allows us to explain them in terms of the properties of a 1D critical manifold which governs the slow evolution of the system.

中文翻译：

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悬浮的一维光子晶体纳米腔中的慢热光机械脉动

我们研究了在氮化硅芯片上制造的悬浮一维（1D）光子晶体纳米腔的非线性光学响应。在低至输入功率的情况下，仍表现出强大的热光非线性特性$2\mu \text{w ^}$并显示出自我维持的脉冲状态以几秒钟的周期出现。随着输入功率和激光波长的变化，时间模式的周期，占空比和形状也会发生变化。这种动力学归因于热光学效应和热光学机械效应之间的多重时间尺度竞争，并且与神经元活动的数学模型中发现的弛豫振荡状态非常相似。我们引入了一个简化的模型，该模型可复制所有实验观察结果，并允许我们根据控制系统缓慢演化的一维临界流形的性质来解释它们。