A disclosed light-emitting device may provide white light with a cyan gap coinciding with a melanopic sensitivity range and thus having reduced melanopic content. The disclosed light-emitting device may include a light source providing violet or blue light with a peak wavelength under 450 nanometers (nm). The disclosed light-emitting device may include at least one down-converter coupled to and located downstream of the light source and configured with a long-wavelength onset to convert the spectrum of the violet or blue light to generate white light with a spectral power content in a 447-531 nm wavelength range that is less than or equal to 10% of a total spectral power content in a 380-780 nm wavelength range. The disclosed light-emitting device may be incorporated in a light engine system that further includes a control system that controls a drive current to the light-emitting device.一種所揭示之發光裝置可提供具有符合一黑視素靈敏度範圍之一青色間隙的白光且因此具有減少之黑視素內容。該所揭示之發光裝置可包含一光源，該光源提供具有低於450奈米(nm)之一峰值波長的紫外線光或藍光。該所揭示之發光裝置可包含至少一個降頻轉換器，該至少一個降頻轉換器耦合至該光源且定位於該光源之下游且經組態而具有一長波長發端以轉換該紫外線光或藍光之光譜，以產生具有在一447 nm至531 nm波長範圍中之一光譜功率內容的白光，該光譜功率內容小於或等於一380 nm至780 nm波長範圍中之一總光譜功率內容的10%。該所揭示之發光裝置可併入一光引擎系統中，該光引擎系統進一步包含一控制系統，該控制系統控制至該發光裝置之一驅動電流。
