A Microlens Array Grating for Miniature Multi-Channel Spectrometers

Abstract

Most existing multi-channel spectrometers are constructed by physically stacking single-channel spectrometers, resulting in their large size, high weight, and limited number of channels. Therefore, their miniaturization is urgently needed. In this paper, a microlens array grating is designed for miniature multi-channel spectrometers. A transmissive element integrating microlens arrays and gratings, the MLAG, enables simultaneous focusing and dispersion. Using soft lithography, the MLAG was fabricated with a deviation of less than 2.2%. The dimensions are 10 mm × 10 mm × 4 mm with over 2000 available units. The MLAG spectrometer operates in the 400–700 nm wavelength range with a resolution of 6 nm. Additionally, the designed MLAG multi-channel spectrometer is experimentally verified to have independently valid cells that can be used in multichannel spectrometers. The wavelength position repeatability deviation of each cell is about 0.5 nm, and the repeatability of displacement measurements by the chromatic confocal sensor with the designed MLAG multi-channel spectrometer is less than 0.5 μm.

A Review: High-Precision Angle Measurement Technologies

“…The principle of the angular scale comb generated by the mode-locked femtosecond laser is shown in Figure 24. The enhancement of the dispersion characteristics of the diffraction grating [200] produces the angular scale comb [11]. (c) four-DOF test bench based on the grating target [179].…”

“…The principle of the angular scale comb generated by the mode-locked femtosecond laser is shown in Figure 24. The enhancement of the dispersion characteristics of the diffraction grating [200] produces the angular scale comb [11]. In a mode-locked laser, each mode has a specific frequency, and each first-order diffraction beam of the diffraction grating has a diffraction angle corresponding to the frequency of each mode.…”