Motionless and fast measurement technique for obtaining the spectral diffraction efficiencies of a grating

Abstract

The measurement of the spectral diffraction efficiencies of a diffraction grating is essential for improving the manufacturing technique and for assessing the grating's function in practical applications. The drawback of the currently popular measurement technique is its slow speed due to the hundreds of repetitions of two kinds of time-consuming mechanical movements during the measuring process (i.e., the rotation of the mechanical arm to capture the light beam and the mechanical variation of the output wavelength of the grating monochromator). This limitation greatly restricts the usage of this technique in dynamic measurement. In this manuscript, we present a motionless and fast measurement technique for obtaining the spectral diffraction efficiencies of a plane grating, effectively eliminating the aforementioned two kinds of mechanical movements. Herein, the proposed solution for removing the first kind of mechanical movement is tested, and the experimental result shows that the proposed method can be successfully used to measure the plane transmission grating's spectral diffraction efficiencies in the wavelength range of 550-750 nm. The method for eliminating the second kind of mechanical movement is not verified in this manuscript; however, we think that it is very straightforward and commercially available. We estimate that the spectral measurement can be achieved on a millisecond time scale by combining the two solutions. Our motionless and fast measuring technique will find broad applications in dynamic measurement environments and mass industrial testing.

High-speed and dynamic measurement of the diffraction efficiency of a grating in a wide wavelength range

“…The measuring theory of our fast measurement method was reported in detail in our previous research [14]. Here we briefly describe the low-speed nature of the current measurement method and the means to achieve high-speed measurement by our technique.…”

“…By successively repeating the above operations at the wavelengths of λ 2 , λ 3 … λ n−1 and λ n , the grating's diffraction efficiency from λ 1 to λ n can be achieved. Because of the repeated mechanical movements, approximate 5 min are needed to obtain the diffraction efficiency of a grating with 151 wavelength sampling points [14].…”

“…In order to realize high-speed measurement of the diffraction efficiency of a grating in a wide wavelength range, in our previous research [14], we introduced the idea of motionless and rapid measurement. Meanwhile we performed a preliminary validation test, and estimated that the expected measurement can be realized on a millisecond timescale.…”