给出了适用性强、工艺上易于实现的单闪耀面宽波段金属光栅的设计方法。基于Rayleigh异常和共振异常两种不同的光栅异常机理,分别讨论了它们出现的条件;在光栅电磁场理论的基础上,数值分析了TE波、TM波闪耀波长的分布规律,得到了闪耀波长与光栅异常和光栅光谱范围的关系;提出了用TM波第一闪耀波长补偿Rayleigh异常或共振异常,实现制作宽波段金属光栅的设计思想。同时,指出了TM波第一闪耀波长对Rayleigh异常补偿效应,只是它对共振异常补偿效应的极限情况。给出了将补偿效应应用于紫外可见分光光度计和红外分光光度计中不同刻线密度宽波段金属光栅的设计实例。实验表明,使用补偿效应法无论在理论设计上还是在工艺实现上都要优于传统的宽波段金属光栅设计方法,可使得用于各个波段的宽波段金属光栅衍射效率都在40%以上。

A new design method with good applicability and easy to implement in technology is presented for broadband metallic diffraction gratings with single blaze surfaces. In consideration of the principles of two types of grating anomalies,Rayleigh type and resonance type,the occurrence conditions of the grating anomalies are discussed. On the basis of electromagnetic theory of gratings,the blaze characters of diffraction efficiency both for TE and TM modes are numerically analyzed,and the relationships among the grating anomalies,the spectrum bands of gratings and the blazed wavelengths is obtained. An idea of designing diffraction gratings is proposed to compensate the Rayleigh anomaly or resonance anomaly with the first blazed wavelength of TM mode. It is pointed out that the compensating effect of the first blazed wavelength of TM mode to Rayleigh anomaly is only the limitation case to the resonance anomaly. The design examples of broadband metallic gratings with different groove densities applied in UV-visible and infrared spectrometers are given.Experiments indicate that the diffraction efficiency of the broadband methallic grating has been over 40% in different spectral bands,which shows that the compensating effect method is better than traditional design methods of broadband metallic gratings,whether in theory design or technology process.