Klein Lukáš, Žídek Karel
Regional Centre for Special Optics and Optoelectronic Systems (TOPTEC), Institute of Plasma Physics, Academy of Sciences of the Czech Republic, Za Slovankou 1782/3, 182 00 Prague 8, Czech Republic.
Rev Sci Instrum. 2020 Jun 1;91(6):063701. doi: 10.1063/1.5132337.
A digital micromirror device (DMD) serves in a significant part of computational optical setups as a means of encoding an image by the desired pattern. The most prominent is its usage in the so-called single-pixel camera experiment. This experiment often requires an efficient and homogeneous collection of light from a relatively large chip on a small area of an optical fiber or spectrometer slit. Moreover, this effort is complicated by the fact that the DMD acts as a diffractive element, which causes severe spectral inhomogeneities in the light collection. We studied the effect of light diffraction via a whiskbroom hyperspectral camera in a broad spectral range. Based on this knowledge, we designed a variety of different approaches to the light collection. We mapped the efficiency and spectral homogeneity of each of the configuration, namely, its ability to couple the light into commercially available fiber spectrometers working in the visible and infrared range (up to 1900 nm). We found the integrating spheres to provide homogeneous light collection, which, however, suffers from very low efficiency. The best compromise between the performance parameters was provided by a combination of an engineered diffuser with an off-axis parabolic mirror. We used this configuration to create a computational microscope able to carry out hyperspectral imaging of a sample in a broad spectral range (400 nm-1900 nm). We see such a setup as an ideal tool to carry out spectrally resolved transmission microscopy in a broad spectral range.
数字微镜器件（DMD）在计算光学装置的很大一部分中用作通过所需图案对图像进行编码的手段。最突出的是它在所谓的单像素相机实验中的应用。该实验通常需要从相对较大的芯片上在光纤或光谱仪狭缝的小区域内高效且均匀地收集光。此外，由于DMD充当衍射元件，这会在光收集过程中导致严重的光谱不均匀性，使得这项工作变得复杂。我们通过扫掠式高光谱相机在宽光谱范围内研究了光衍射的影响。基于这些知识，我们设计了多种不同的光收集方法。我们绘制了每种配置的效率和光谱均匀性，即其将光耦合到工作在可见光和红外范围（高达1900nm）的商用光纤光谱仪中的能力。我们发现积分球可提供均匀的光收集，然而其效率非常低。工程扩散器与离轴抛物面镜的组合在性能参数之间提供了最佳折衷。我们使用这种配置创建了一台计算显微镜，能够在宽光谱范围（400nm - 1900nm）内对样品进行高光谱成像。我们将这样的设置视为在宽光谱范围内进行光谱分辨透射显微镜检查的理想工具。
