both transmission and fluorescence microscopy. Other developments in this period include the first holographic demonstration by Sadao Aoki and Seishi Kikuta in Japan, the first TXMs using zone plates by Schmahl et al., and Stony Brook's experiments in STXM. The uses of synchrotron light sources brought new possibilities for X-ray microscopy in the 1980s. However, as new synchrotron-source-based microscopes were built in many groups, people realized that it was difficult to perform such experiments due to insufficient technological capabilities at that time, such as poor coherent illuminations, poor-quality x-ray optical elements, and user-unfriendly light sources. Entering the 1990s, new instruments and new light sources greatly fueled the improvement of X-ray microscopy. Microscopy methods including tomography, cryo-, and cryo-tomography were successfully demonstrated. With rapid development, X-ray microscopy found new applications in soil science, geochemistry, polymer sciences, and magnetism. The hardware was also miniaturized, so that researchers could perform experiments in their own laboratories. Extremely high-intensity sources of 9.25 keV X-rays for X-ray phase-contrast microscopy, from a focal spot about 10 μm × 10 μm, may be obtained with a non-synchrotron X-ray source that uses a focused electron beam and a liquid-metal anode. This was demonstrated in 2003 and in 2017 was used to image mouse brain at a voxel size of about one cubic micrometer (see below). With the applications continuing to grow, X-ray microscopy has become a routine, proven technique used in environmental and soil sciences, geo- and cosmo-chemistry, polymer sciences, biology, magnetism, material sciences. With this increasing demand for X-ray microscopy in these fields, microscopes based on synchrotron, liquid-metal anode, and other laboratory light sources are being built around the world. X-ray optics and components are also being commercialized rapidly. Instrumentation X-ray optics Synchrotron light sources Advanced Light Source The Advanced Light Source (ALS) in Berkeley, California, is home to XM-1, a full-field soft X-ray microscope operated by the Center for X-ray Optics and dedicated to various applications in modern nanoscience, such as nanomagnetic materials, environmental and materials sciences and biology. XM-1 uses an X-ray lens to focus X-rays on a CCD, in a manner similar to an optical microscope. XM-1 held the world record in spatial resolution with Fresnel zone plates down to 15 nm and is able to combine high spatial resolution with a sub-100ps time resolution to study e.g. ultrafast spin dynamics. In July 2012, a group at DESY claimed a record spatial resolution of 10