Nowadays, the continuous evolution of synchrotron radiation sources has resulted in a dramatic increase of brilliance and degree of spatial coherence with respect to older designs. The availability of such intense coherent X-ray beams has triggered the development of wave splitting interferometers similar to the classical double-slit Young’s experiment [1-4]. The bilens interferometer consisting of two parallel compound refractive lenses (CRL) and characterizing by high efficiency even in hard X-rays is a remarkable demonstration of such optical devices .
In this work, the phase-sensitive X-ray imaging technique based on the bilens interferometer is developed . The essence of the method consists of scanning a sample, which is set upstream of the bilens across the beam of one lens of the interferometer by recording changes in the interference pattern using a high-resolution image detector. The proposed approach allows acquiring the absolute value of a phase shift profile of the sample with a fairly high phase and spatial resolution. The possibilities of the imaging technique were studied theoretically and experimentally using fibres with different sizes as the test samples at the ESRF ID06 beamline with 12 keV X-rays. The corresponding phase shift profile reconstructions and computer simulations were performed. The experimental results are fully consistent with theoretical concepts and appropriate numerical calculations. Future improvements and applications of the interferometric imaging technique are discussed.
 Leitenberger, W., Kuznetsov, S. M., & Snigirev, A. (2001). Interferometric measurements with hard X-rays using a double slit. Optics communications, 191(1-2), 91-96.
 Lyubomirskiy, M., Snigireva, I., & Snigirev, A. (2016). Lens coupled tunable Young’s double pinhole system for hard X-ray spatial coherence characterization. Optics express, 24(12), 13679-13686.
 Lyubomirskiy, M., Snigireva, I., Kuznetsov, S., Yunkin, V., & Snigirev, A. (2015). Hard x-ray single crystal bi-mirror. Optics letters, 40(10), 2205-2208.
 Suzuki, Y. (2004). Measurement of x-ray coherence using two-beam interferometer with prism optics. Review of scientific instruments, 75(4), 1026-1029.
 Snigirev, A., Snigireva, I., Kohn, V., Yunkin, V., Kuznetsov, S., Grigoriev, M. B., ... & Detlefs, C. (2009). X-ray nanointerferometer based on si refractive bilenses. Physical review letters, 103(6), 064801.
 Zverev D., Snigireva I., Kohn V., Kuznetsov S., Yunkin V., Snigirev A., (2020) X-ray phase-sensitive imaging using a bilens interferometer based on refractive optics. Accepted for publication in journal Opt. Express